If you look up the word "burger," you'll find a variety of definitions. They all seem to boil down to a dish made with a patty of beef, or some other savory ingredient, that's cooked and served inside a split bun or roll with various condiments.

While the definition is broad, for this story we are going to focus on the "some other savory ingredient" variety of burgers.

Non-beef burgers are nothing new. A grilled chicken breast, served on a bun, is technically a burger. Ground turkey, formed into a patty and tucked into something breadlike, is also a burger.

A quick glance at any grocery store meat department will reveal several brands of plant-based patties, which, when cooked and placed between a perfectly toasted, split vegan roll, is, yep, you guessed it — a burger.

All of the above can be delicious and worthy of its burger status, but there are so many other options to explore.

Where's the meat?

My first exposure to a vegetarian burger, many years ago, consisted of a mushy, bland black bean patty topped with some type of wilted green leaf between a dry whole wheat bun. I'm still traumatized over the distance between what I imagined I was going to be biting into and the reality.

It took a long time to work up the desire to explore a non-meat option again, but when I did, I realized that category of burger had improved exponentially. Yes, the plant-based versions that look and taste like meat can be quite good, but there are also so many out-of-the-box burger experiences, too, with patties that aren't trying to imitate animal protein.

Such is the case with Crispy Roasted Portobello Risotto Burgers. There's nothing new about portobello mushrooms standing in for a beef patty, but this recipe brings so much more to the table.

At the center is indeed a roasted portobello mushroom, but in this case it's stuffed with Fontina cheese and covered in risotto and then breaded and pan-fried to golden perfection.

Admittedly, this burger has a lot going on. The center is gooey and cheesy, with a meaty bite from the mushroom, but it's the risotto cake surrounding it — crispy on the outside, tender on inside — that brings this burger home.

Sorry, arancini lovers, but this is the best possible use of leftover risotto. There, I said it. In fact, this burger is so good, with the addition of peppery arugula and a slathering of roasted garlic mayo (easy to do when you're already roasting the mushrooms), that I would happily make risotto just to use it in this burger.

Under the sea

Seafood is another wonderful option in the world of alternative burgers. Many of us started our exploration of non-beef burgers in the drive-thru line of a certain fast-food restaurant. And the hot, crispy fish fillet sandwich, served on a soft white bun with a swipe of mayo, did not disappoint.

Now I'm a little more discerning in my tastes, and when I'm making my own seafood burgers, outside of the simplest versions made from a grilled piece of tuna, salmon or other firm-fleshed fish, I often take the crabcake approach.

This calls for chopping a firm-fleshed fish finely, seasoning it, binding it with breadcrumbs and egg and forming it into a patty. Sometimes I'll bread it and fry it. Other times I'll grill it or sauté it until just cooked through.

When shellfish is the seafood of choice, a binding isn't always necessary, as is the case with Shrimp Burgers with Red Chile Slaw.

Unlike crab, shrimp contains a high amount of natural gelatin. All you need to do is purée a portion of the shrimp, add more chopped shrimp and a few other seasonings, and you have a patty that holds together on its own. It can be cooked any number of ways, without the binders and fillers that often make a patty soft and dilute the flavor of the seafood. This burger is all shrimp.

Meat beyond beef

If you're still craving a meaty, juicy, dripping-down-your-chin burger, it might be time to give lamb a try. Because lamb might be the most flavorful of all the non-beef meat options, it really needs nothing but salt and maybe a fresh grinding of pepper to be fantastic.

Since I live to gild the lily, I can't help but take things step or two further. But those steps are pretty delicious.

I like to grill my Lamb Burgers with Pickled Grilled Red Onions and Blue Cheese Mayo. The smoke and char from the grill dial up the flavor of the lamb while somehow turning down any gaminess.

And since the fire has already been started, I throw on a sliced red onion, which I then briefly pickle. This quick pickle brings a delightfully bright note, which is the perfect foil to the rich lamb. Oh, and while I'm at it, I also top this already over-the-top burger with a dollop of blue cheese mayo. The combination is so absolutely addictive, no one will miss the beef.

Crispy Roasted Portobello Risotto Burgers

Serves 4.

A great way to use leftover risotto, these meatless burgers have a few steps, but each one is easy and the end result — crispy, cheesy, hearty burgers — is well worth the effort. While almost any leftover risotto will work, Parmesan Risotto (recipe follows) is a wonderful option. From Meredith Deeds.

• 1 head garlic

• 1 tbsp., plus 1 tsp. extra-virgin olive oil

• 4 medium-sized portobello mushrooms, cleaned

• 1/2 tsp. salt, divided

• 1/2 tsp. freshly ground black pepper, divided

• 1/3 c. mayonnaise

• 1 tsp. lemon juice

• 1/2 c. shredded Fontina cheese

• 3 c. leftover risotto, chilled

• 1/2 c. all-purpose flour

• 2 large eggs, beaten

• 1 c. panko breadcrumbs

• Vegetable oil

• 4 (4-in.) focaccia squares, cut in half horizontally, or 4 focaccia buns, split

• Arugula

Directions

Preheat oven to 400 degrees.

Using a sharp knife, cut 1/4 to a 1/2 inch from the top of garlic cloves to expose the tops of them. Place the head on a small square of foil. Drizzle with 1 teaspoon olive oil and bring up foil to fully enclose garlic. Place on baking pan and bake for 30 to 40 minutes, or until the cloves are very soft. Remove from oven and let cool.

Meanwhile, remove the stems of the mushrooms and, using the tip of a small spoon, carefully scrape away the gills on the inside. Brush all over with remaining 1 tablespoon olive oil and season with 1/4 teaspoon salt and 1/4 teaspoon pepper. Place, rounded side down, on a lightly oiled baking sheet. Place in the oven and roast for 20 to 25 minutes, until the mushrooms are softened and lightly browned. Remove from oven and let cool.

Squeeze the garlic pulp out of the heads into a small bowl and mash with a fork. Add the mayonnaise and lemon juice and stir to combine. Set aside.

Place 2 tablespoons of cheese into the gill side of each roasted mushroom. Wet the palm of your hands with water and form 2/3 cup of the chilled risotto into a thin patty, larger than the mushroom. Place the patty on top of the cheese-filled side of the mushroom and bring the risotto around to enclose the mushroom, using a little more risotto if necessary. Refrigerate for 30 minutes.

In three separate shallow dishes, place flour mixed with remaining 1/4 teaspoon salt and 1/4 teaspoon pepper, eggs and panko. Dredge each risotto-mushroom patty in the flour first, then the egg and finally the panko.

Heat 1/2-inch of vegetable oil in a 12-inch nonstick skillet over medium heat until it reaches 350 degrees. Carefully place risotto-mushroom patties in the pan and cook, about 3 to 4 minutes a side, until browned. Drain on paper towels.

Spread the roasted garlic mayo on the cut sides of the focaccia. Build each burger on the focaccia with a crispy risotto patty and arugula.

Parmesan Risotto

Serves 6 as a side dish.

From Meredith Deeds.

• 5 c. low-sodium chicken or vegetable broth, plus more if necessary

• 1 1/2 c. water

• 4 tbsp. unsalted butter, divided

• 3/4 c. finely chopped shallots

• 3/4 tsp. salt

• 1 clove garlic, finely chopped

• 2 c. arborio rice

• 3/4 c. dry white wine

• 1 c. freshly grated good-quality Parmesan cheese (about 2 oz.)

Directions

In a medium saucepan, combine broth and water. Bring to a boil over medium heat. Reduce the heat to lowest setting to keep liquid warm.

Heat 2 tablespoons butter in a large, heavy saucepan or Dutch oven over medium heat. Add shallot and salt and cook, stirring frequently, until onion is softened, 3 to 5 minutes. Add garlic and stir until fragrant, about 30 seconds. Add rice and cook, stirring frequently, until grains are mostly translucent, about 3 to 5 minutes. Add the wine and cook, stirring, until evaporated.

Ladle one cup of the warm stock into the rice and cook, stirring gently without stopping, until the rice has absorbed the liquid, 2 to 3 minutes. Repeat this process, adding more stock a ladleful at a time, until the rice is al dente, 17 to 19 minutes. Stir in the Parmesan and remaining 2 tablespoons butter. Taste for seasoning. Add another 1/4 cup broth into the risotto if you prefer it on the saucier side. Serve immediately, garnished with more Parmesan, if desired.

Shrimp Burgers with Red Chile Slaw

Serves 4.

Creamy, crunchy slaw, with just the right amount of kick, thanks to the addition of a Fresno chile, is a delicious accompaniment to these delightful shrimp burgers. From Meredith Deeds.

For the burgers:

• 1 lb. medium shrimp, peeled and deveined, tails removed

• 1 clove garlic, finely chopped

• 1/2 tsp. salt

• 1/4 tsp. cayenne

• 1/4 c. finely chopped shallots

• 1/2 c. rice flour

• Vegetable oil

• 4 hamburger buns

For the slaw:

• 1/4 c. mayonnaise

• 1 tbsp. whole-grain mustard

• 2 tsp. lemon juice

• 1 1/2 tsp. honey

• 1/4 tsp. salt

• 3 c. shredded cabbage

• 1/4 c. chopped green onions

• 1 Fresno chile, seeded and thinly sliced

Directions

Place half the shrimp, garlic, salt and cayenne in the bowl of a food processor and pulse until puréed. Add remaining half of shrimp and shallots and pulse until shrimp is chopped, but still chunky. Transfer mixture to a bowl and chill for 30 minutes.

Meanwhile, in a medium bowl, whisk together the mayonnaise, mustard, lemon juice, honey and salt. Add cabbage, green onions and chile. Toss to combine.

Form chilled shrimp mixture into 4 patties. Place rice flour in a shallow bowl. Dredge patties in flour.

In a 12-inch skillet, heat 1/4 inch oil to 350 degrees. Place patties in hot oil and cook until golden brown, about 3 minutes per side. Transfer to paper towel-lined plate.

Serve burgers on buns topped with slaw.

Lamb Burgers with Pickled Grilled Red Onions and Blue Cheese Mayo

Serves 4.

Pickling the grilled onion topping cuts through the richness of the lamb and the blue cheese, bringing a perfect balance to these decadent burgers. From Meredith Deeds.

For the mayo:

• 1/4 c. mayonnaise

• 1/4 c. crumbled blue cheese

• 1 tsp. finely chopped garlic

• 1/8 tsp. freshly ground black pepper

For the pickled onions:

• 1/2 c. white vinegar

• 1/2 c. water

• 1/2 c. sugar

• 1 tsp. salt

• 1 large red onion, cut into 1/4-in. slices

• 1 tbsp. vegetable oil

For the burgers:

• 1 1/4 lb. ground lamb

• Salt and freshly ground black pepper

• 4 hearty hamburger buns, toasted

Directions

Prepare grill for medium-high direct heat.

In a small bowl combine all the mayonnaise, blue cheese, garlic and pepper. Cover and chill until ready to use.

In a small saucepan, combine the vinegar, water, sugar and 1 teaspoon salt. Cook over medium heat, stirring, until sugar is dissolved.

Brush both sides of onion slices with oil and place on grill. Cook until tender and charred in spots. Place in a bowl and pour vinegar mixture over the top. Press down on the onion to submerge and let sit while burgers cook.

Form ground lamb into 4 patties and season with salt and pepper. Place on grill and cook to desired doneness.

Serve on buns with drained pickled onions and mayo.

Meredith Deeds is a cookbook author and food writer from Edina. Reach her at meredithdeeds@gmail.com. Follow her on Instagram ­at @meredithdeeds