Sweet potato pies are classic, legendary, tradition, basically any number of adjectives that imply lineage and amazing. There is a reason that grandparents often boast of how tasty their sweet potato pies are and it isn’t for the sake of ease. If done completely from scratch, these babies can take some time. But I submit that it is worth every minute and every ounce of effort.
This pie has three major steps, which all have a mountain of science surrounding them, but I think I’ll focus on the science behind making the crust. The major difference between biscuit dough and pie dough is the amount of water. Pie crust should contain very little water because water turns into steam which adds leavening to the crust. Leavening is not what we want here. For this reason, before pie crusts are placed in the oven they are docked with holes to allow steam an outlet.
You will also notice that this pie crust contains both butter and shortening (Crisco). The butter is cut into the dough first to produce small beads of flour and butter. In this way butter is acting as a shortening agent to minimize the formation of gluten.
Somewhat ironically, Crisco is not the primary shortening agent in this recipe. That is butter’s job. The job of Crisco is to create flakiness. We cut Crisco into the dough second to produce large chunks of flour and Crisco. When high enough temperatures are reached, the Crisco chunks (and the butter beads to a lesser extent) melt between layers of flour in the pie crust. The end result being a flaky product.
AP Flour- 1 ¼ cup
Salt- ½ tsp
Unsalted Butter- 6tbs
Shortening- 2 tbs
Ice Water- 2 tbs
- Freeze the butter and shortening for 10 minutes (while this is freezing begin peeling, chopping, and boiling sweet potatoes)
- Combine the flour and salt in a medium sized bowl.
- Take the butter and shortening out of the freezer. Then grate the butter into the flour. Use your hands to rub the butter into the flour until butter is thoroughly incorporated and small clumps are present.
- Cut the shortening into small pieces then insert into flour. Rub the shortening into the flour. The shortening should form relatively large chunks compared to the small clumps of butter.
- Add the ice water to the flour mixture and stir until a ball forms.
- Flour a piece of parchment or wax paper. Then roll the dough into a 10 to 12 inch circle. Place the pie pan edges down over the pie dough then flip the pan over. This should allow the pie dough to enter into the pie pan perfectly (You may have to use your hands to carefully remove it). Trim the edges of the pie dough.
- Use a fork to poke 8 sets of holes into the crust. Then put pie pan in freezer for 30 minutes
Sweet Potato Custard
1 1/4 pounds of potatoes (about 2 large potatoes)
1 1/4 cups sugar
1/2 stick melted butter
3 egg yolks
1 teaspoon vanilla extract
1/4 teaspoon salt
3/8 teaspoon ground cinnamon
1/4 teaspoon ground all spice
½ cup milk
½ cup buttermilk (can replace with whole milk, if unavailable)
3 egg whites (room temperature)
- At this point the pie dough should be in the freezer and the sweet potatoes should be done cooking. Preheat the oven to 350F.
- Drain the sweet potatoes then mash them. Mix in 1 cup of sugar, egg yolks, butter, vanilla extract, salt, all-spice, and cinnamon. Next mix in the milk and buttermilk.
- When the pie dough is ready, pour the filling into the pie pan then place in the oven. Allow the pie to bake until the custard sets, about 40-50 minutes. (A toothpick inserted in the middle should come out almost clean.)
- After the pie is done baking allow to cool to room temperature. This is when you should start on the meringue.
- While the custard is cooling, whip the meringue. For the meringue, whip using stand or hand mixer at medium high speed until foam begins to form. After foam begins to form, add cream of tartar and turn mixer on high. As the foam gains in volume, begin adding remaining sugar in 2-4 tablespoon increments until the sugar is added. Stop mixing when the meringue forms soft peaks.
- Add the meringue to the top of the cooled pie. Make sure the crust is covered by the meringue. Sprinkle with a pinch of granulate sugar. Then bake at 350F for 10-15 minutes or until golden brown streaks form.