We have a complicated relationship with fat, or more precisely, with fats.

We fear they’ll make us plump, which indeed is a consequence of regular overindulgence.

We fear they’ll clog our hearts, which, see above.

But boy, do we complain if a pie crust tastes like cardboard, if a cake is dry, if biscuits could double as hockey pucks. We want flakiness and flavor and tenderness, all of which come from including oil, butter, shortening or lard in our baked goods.

The prudent choice is to indulge rarely, but well, which means making sure we’re using the right fats in the right proportions when we bake.

Here’s a primer about the basic fats (and a great recipe).

Butter: This is the queen of fats, not so much because of its ability to make a flaky pastry, but because it adds so much flavor and richness.

Grocery coolers are stocked with sweet cream butter, but that doesn’t mean it’s been sweetened, only that it’s made from pure cream. The term differentiates it from cultured butter, which is made from sour cream.

Most recipes call for using unsalted butter, a directive that seems confusing when those same recipes also call for salt. The reason is that the amount of salt added to butter varies across brands. Using unsalted butter lets you better control the level of saltiness because you’re the one adding the desired amount.

Because butter melts easily, it’s a must for cakes as it creams and fluffs so well when beaten with sugar, creating tenderness.

But when used in pastry crusts, butter should be well chilled so that it can be mixed into the flour while retaining its identity. That’s why recipes often say to mix until the butter is in pea-sized pieces and not a moment longer. The air and water in those tidbits of butter will expand in the oven’s heat, creating flakiness.

Lard: This is a more homespun fat. It comes not from the cream of long-lashed cows, but is the result of rendering or melting hog fat, then straining it and letting it solidify. Some people don’t like this image.

Lard is grainier than butter, which makes it undesirable for tender cakes. But that graininess comes from the lard solidifying into crystals that, while still small, are superior to butter at separating layers of dough such as in pies and tarts. Lard makes the best flakes.

Many recipes seek the best of both worlds, calling for a 50-50 split of butter for flavor and lard for flakiness. But because lard isn’t always as available as butter, shortening is a common substitute, unless all-butter is preferred.

Shortening: This is manufactured from vegetable oils, usually soybean or cottonseed oils, using a process that turns them into a solid. It’s 100 percent fat, so it makes very tender baked goods. Long spurned for harboring trans-fats, shortening now is trans-fat-free with the oils being fully hydrogenated.

Shortening also has larger crystals than butter, but not as large as those in lard. But it is readily available and economical.

While there are several brands, Crisco is overwhelmingly the most popular shortening on the market, chosen by almost nine in 10 users in 2017.

Margarine is similar to shortening, but may still have trans-fats, which makes label-reading a must. Yet, like shortening, it’s also vegan. Still, its low melting point makes it the least desirable solid fat for baked goods. And some margarines are sold whipped with air, which makes them unsuited for baking entirely.

Oil: This is 100 percent fat and is particularly suited for certain baked goods such as quick breads and muffins, where it creates a moist, dense crumb.

While it lacks the flake-making water or air particles of other fats, the plus side is that oil crusts don’t become soggy, making them good for juicy pie fillings.

Some oil pie crusts also can be mixed right in the pan and patted into place, bypassing the sometimes frustrating act of rolling and lifting pastry into a pie plate.

So that’s the skinny on fats. Bottom line, they add flavor and tenderness to your baked goods. And if you keep a slice of pie or a slab of cake for the occasional indulgence, why not make it the best dessert it can be?

Here’s a pie crust that can be made with all butter or with a 50-50 proportion of butter and lard. Double the recipe to make enough crust for a slab pie, which will feed a horde of people at summer picnics.

Blueberry-Rhubarb Slab Pie

Serves 12 to 16.

Note: This dough recipe makes enough for 1 double-crust 9-inch pie. For the larger slab pie, you’ll need to make the recipe twice, one for each crust. The pastry is best when allowed to chill overnight. Slightly adapted from “The Four and Twenty Blackbirds Pie Book,” by Emily Elsen and Melissa Elsen.

• 2 recipes of Pie Crust (recipe below)

• 1 tbsp. soft butter, for pan

• 1 1/2 to 2 lb. rhubarb, cut into 1/2-in. pieces (4 to 5 c.)

• 4 to 5 c. blueberries (about 1 1/2 lb. fresh)

• 1 large baking apple

• 1 c. light brown sugar, packed

• 2/3 c. granulated sugar

• 1/2 tsp. ground allspice

• 1/2 tsp. ground cinnamon

• 1/2 tsp. ground cardamom

• 1/8 tsp. ground cloves

• 3/4 tsp. salt

• 7 tbsp. cornstarch or arrowroot

• 2 tbsp. fresh lemon juice

• 2 to 3 dashes cocktail bitters, if desired

• Egg wash (1 large egg whisked with 1 tsp. water and a pinch of salt)

• Demerara or other coarse sugar for finishing

Directions

Remove both rectangles of chilled dough from the refrigerator.

Butter an 11 1/2- by 16-inch sheet pan with a 1-inch rim, then line with parchment paper.

On a lightly floured work surface, unwrap 1 rectangle of dough and roll into a 16- by 20-inch rectangle. Fit the dough inside the sheet pan, letting the edges overhang.

Roll the second dough rectangle into a 13- by 17-inch rectangle. Place on a second sheet of parchment paper, then lay that on top of the bottom crust and place in the refrigerator to chill while preparing the filling.

Combine rhubarb and blueberries in a large bowl, crushing about half of the blueberries with your hands. Peel and grate the apple, then add to the mixture, along with both sugars, allspice, cinnamon, cardamom, cloves, salt, cornstarch, lemon juice and bitters; mix thoroughly.

Remove the dough from the refrigerator and set the top crust aside. Pour filling into the sheet pan. Position the top crust rectangle squarely over the filling, then roll and pinch the excess crust inward to create an edge all the way around the pan. Crimp this edge as desired. Create several steam vents in a decorative pattern using a sharp paring knife.

Chill pie in the refrigerator for 10 to 15 minutes to set the pastry.

Meanwhile, place oven racks in the bottom and center positions and preheat to 425 degrees.

Brush the chilled pastry with the egg wash and sprinkle with desired amount of sugar to finish. Place pie on lowest oven rack and bake for 20 to 25 minutes. Lower the oven temperature to 375 degrees, move the pie to the center rack and continue to bake until the pastry is a deep golden brown and juices are bubbling, 30 to 35 minutes longer.

Allow to cool completely on a wire rack for 2 to 3 hours. Pie will keep refrigerated for 3 days or at room temperature for 2 days.

Pie Crust

Makes 2 (9-inch) pie crusts.

Note: This dough recipe makes enough for 1 double-crust 9-inch pie. For the larger slab pie (recipe above), you’ll need to make the recipe twice, one for each large crust. Resist the urge to make both batches as one; it’s too much dough to handle well. The pastry is best when allowed to chill overnight. Slightly adapted from “The Four and Twenty Blackbirds Pie Book,” by Emily Elsen and Melissa Elsen.

• 2 1/2 c. flour

• 1 tsp. salt

• 1 tbsp. sugar

• 1/2 lb. (2 sticks) cold unsalted butter, cut into 1/2-in. pieces (or 1 stick cold butter with 1/2 c. very cold or frozen lard, cut into 1/2-in. pieces).

• 1 c. cold water

• 1/4 c. cider vinegar

• 1 c. ice

Directions

Stir the flour, salt and sugar together in a large bowl. Add the butter (or butter and lard) pieces and coat with the flour mixture using a bench scraper or spatula. With a pastry blender, cut the butter into the flour mixture, working quickly until mostly pea-size pieces of butter remain (a few larger pieces are OK; be careful not to overblend).

Combine 1 cup water, cider vinegar and ice in a large measuring cup or small bowl.

Sprinkle 2 tablespoons of the ice water mixture over the flour mixture, and mix and cut it in with a bench scraper or spatula until it is fully incorporated. Add more of the ice water mixture, 1 to 2 tablespoons at a time, using the bench scraper or your hands (or both) to mix until the dough comes together in a ball, with some dry bits remaining. Squeeze and pinch with your fingertips to bring all the dough together, sprinkling dry bits with more small drops of the ice water mixture, if necessary, to combine. (You might not use all of the water mixture.)

Shape the dough into a small rectangle, wrap in plastic, and refrigerate for at least 1 hour, preferably overnight, to give the crust time to mellow.

If making a slab pie, make a second batch of the recipe.

If making a 9-inch double-crust pie, divide the dough in half before shaping each portion into flat discs. Wrapped tightly, the dough can be refrigerated for 3 days or frozen for 1 month.

Nutrition information per each of 16 servings:

Calories 500 Fat 25 g Sodium 430 mg

Carbohydrates 67 g Saturated fat 15 g Total sugars 30 g

Protein 5 g Cholesterol 70 mg Dietary fiber 3 g

Exchanges per serving: ½ fruit, 2 starch, 2 carb, 4½ fat.

Kim Ode is a freelance journalist and baker in Edina. She can be reached at odekim@gmail.com.