The key to big flavor in steak fajitas? High heat and caramelization

I can't tell you how many times I've set off the smoke alarm in my kitchen, but I'm sure the number is impressive. Usually (but not always), it's not because something is burning. It's because I often cook with high heat.

High heat brings caramelization in the form of browning, sometimes even charring. And caramelization brings flavor to many dishes, especially this week's Steak, Mushroom and Poblano Fajitas.

Fajitas are an iconic Tex-Mex dish that often elicits oohs and aahs in Mexican restaurants, as hot platters of sizzling meat and veggies work their way through the dining room.

Those platters are typically made of cast iron — smoking hot cast iron. That heat creates those irresistible charred bits on, in this case, chunks of lime-marinated steak, poblano peppers, onions and sliced mushrooms.

If you don't have a big cast-iron skillet, any other heavy skillet will do, although nonstick does not work well for this dish. That being said, any kitchen without a cast-iron skillet is missing a key piece of equipment that typically costs far less than a decent quality stainless-steel pan. It's a worthwhile investment that will last a lifetime.

While most fajitas consist of a protein and sweet bell peppers and onions, this version replaces the standard bell peppers with poblanos, which are usually mild in heat but more intensely flavored. Mushrooms, which aren't usually found in fajitas, bring an earthy flavor that seems to marry the smokiness of the meat with the deep but bright flavors of the peppers.

I like to serve my fajitas with guacamole, pico de gallo, fresh cilantro leaves and lime wedges on the side.

Serves 4 to 6.

Note: Mushrooms and poblano peppers give these steak fajitas a rich, deep, earthy flavor. This recipe requires a little extra time for the meat to marinate. From Meredith Deeds.

• 2 tbsp. fresh lime juice

• 1 tbsp. chili powder

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

• 1  1/4 lb. skirt or flank steak, cut crosswise into 4-in.-wide pieces

• 3/4 tsp. salt, divided

• 3 tbsp. vegetable oil, divided

• 8 oz. sliced mushrooms

• 2 poblano peppers, stemmed, seeded, and cut into 1/2-in.-wide strips

• 12 (6-inch) flour tortillas, warmed

Garnishes, as desired:

• Cilantro leaves

• Guacamole

• Pico de gallo

Directions

To marinate the steak: In a small bowl, combine the lime juice, chili powder, 1/4 teaspoon pepper and garlic. Place the steak in a large, sealable bag. Pour the lime mixture into the bag and turn it over one or two times to coat the steak. Refrigerate for at least 30 minutes or up to 4 hours.

Remove steak from marinade, pat dry with paper towels and season both sides with 1/2 teaspoon salt.

Heat a 12-inch cast-iron skillet over high heat for 2 minutes. Add 1 tablespoon oil to the skillet. The add the steak and cook, turning once or twice, for 7 to 10 minutes, or to desired doneness (lower the heat to medium if skillet is smoking too much). Typically, 4 minutes per side will result in a medium-rare doneness. Transfer the steak to a cutting board and let rest while the vegetables are cooking.

Carefully wipe out skillet with paper towels. Heat 1 tablespoon oil in the skillet over high heat. Add the mushrooms to the skillet and cook, in an even layer, for 4 to 5 minutes, turning once or twice, until browned. Transfer to a plate.

Slice the steak, across the grain, into thin slices. Transfer to a serving plate. Serve with warm tortillas with guacamole, pico de gallo and lime wedges on the side, as desired.