Introduction: Sweet Potato Pie

About: Eric J. Wilhelm is the founder of Instructables. He has a Ph.D. from MIT in Mechanical Engineering. Eric believes in making technology accessible through understanding, and strives to inspire others to learn …

Each year at Instructables we have a holiday cook-off, where everyone makes a traditional holiday dish and we compete to see whose is the best and which recipe will climb the pageview ranks.  I needed something slightly different than my award-winning Pumpkin Pie, and so choose Sweet Potato Pie.

This Sweet Potato Pie recipe is a triangulation of three recipes:  The Best Sweet Potato Pie from Cooks Illustrated; Sweet Potato Meringue Pie from Gourmet Today; and Sweet Potato Pecan Pie from Rosie's Bakery All-Butter, Fresh Cream, Sugar-Packed, No-Holds-Barred Baking Book.

I thought Cooks Illustrated's recipe didn't have enough fat and the others were lacking in flavors besides sweet.  Putting them together yields a pie that's rich without being heavy and is clearly sweet potato (including small chucks of sweet potato flesh), but has complimentary flavors of whiskey, molasses, and caramelized brown sugar. 

Step 1: Ingredients

Sweet Potato Pie Filling
2 pounds sweet potatoes (see the size of my 6 in the images)
4 tablespoons unsalted butter at room temperature
3 large eggs
2 egg yolks
1 cup sugar
1/2 - 1 teaspoon fresh ground nutmeg
1/4 teaspoon salt
3 tablespoons whiskey (Cooks Illustrated suggests bourbon; use whatever whiskey type you've got!)
1 tablespoon molasses
1 teaspoon vanilla extract
1/3 cup whole milk
1/3 cup heavy whipping cream
1/4 cup packed dark brown sugar

Crust
1 1/4 cups unbleached flour
3/4 cup flour
1/2 teaspoon salt
1 tablespoon sugar
6 tablespoons cold unsalted butter, cut apart in a bunch of small pieces
1/4 cup vegetable shortening - non-hydrogenated palm oil if you can find it; Crisco or crisco-like shortening if you can't
2 tablespoons cold vodka
2 tablespoons water

Step 2: Make the Pie Crust

Follow the Pie Crust instructions from Pumpkin Pie.  Or check out these other Instructables: Pie Crust, A Quick Pie Crust, or How to Make Pie Crust.

In abbreviated form:

-- mix these together first in a food processor --
3/4 cup flour (3/4 cup of the 1 1/4 cups total unbleached flour)
1/2 teaspoon salt
1 tablespoon sugar
-- next add these, and food process until it looks like cottage cheese, and there's no uncoated flour --
6 tablespoons cold unsalted butter, cut apart in a bunch of small pieces
1/4 cup vegetable shortening - non-hydrogenated palm oil if you can find it; Crisco or crisco-like shortening if you can't
-- next add this and process until it's fully incorporated --
remaining 1/2 cup flour
-- scrape the dough out of the food processor with a spatula and mix in these --
2 tablespoons cold vodka
2 tablespoons water

Wrap the dough in plastic wrap and refrigerate for at least 45 minutes.  Roll the dough out on a well-floured surface, or silicon work pad, and then place it in a pie dish and flute the edges.  Refrigerate for another 15 minutes at any point that the butter in the dough starts to melt or the dough feels greasy.

Dimple the surface of the pie with a fork -- this helps prevent the aluminum foil from tearing the crust when you remove it.  Line the crust with foil and fill it with pie weights, dried beans, or coins to keep the crust from changing shape as it bakes. 

Bake at 400°F in a pre-heated oven on the lowest rack setting for 15 minutes.  Remove the foil and pie weights, rotate the crust, and bake for another 5 - 10 minutes, or until the pie is golden brown.  This is called "blind baking."

Step 3: Pre-Cook Sweet Potatoes

While the pie crust dough is first cooling in the refrigerator, or whenever your Thanksgiving Gantt chart says so, work on the pie's filling.

You need to soften the sweet potatoes to more easily mix their flesh in with the rest of the filling.

Stab the sweet potatoes with a fork, and microwave them for 5 - 10 minutes -- depending on the strength of your microwave -- or until soft but not mushy. Cut them in half and scoop out the flesh.  I held my still-hot potatoes with a pot-holder while scooping.  Mix in the butter and lightly mash, but don't puree. 

Step 4: Mix Together Eggs, Sugar, and Spices

Mix the eggs and egg yolks, sugar, nutmeg, salt, whiskey, molasses, and vanilla.  Whisk it all together.  Then whisk in the milk and whipping cream.  Finally, mix the sweet potato flesh and butter with the egg and milk mixture.  Whisk everything, but again, don't puree as you're aiming to have chunks of sweet potato left in the filling.

Step 5: A Layer of Brown Sugar in the Pie Crust

With the pie crust still hot from the oven (or if already blind baked and cooled, reheated for 5 minutes), spread an even layer of brown sugar over the bottom of the crust.  This layer with melt and provide a fun "surprise" at the bottom of the pie.

Step 6: Add Filling and Bake

Pour the filling over the brown sugar, and bake the pie at 350°F until it just barely jiggles in the center when shaken.  I checked after 45 minutes, and found it done at 52 minutes.

Step 7: Cool the Pie

If you want a perfect-looking pie, you need to cool it slowly on a wire rack (to minimize uneven cooling through conduction via the bottom).  I always think, "it's cooler outside, so I should put the pie outside to cool."  This will result in a cracked pie, as shown.   Cool it slowly, and prepare for this to take 2 or 3 hours. 

Step 8: Serve

Serve the pie and admire the chucks of sweet potato and melted brown sugar layer. 

If you're cooking Thanksgiving dinner for a crowd, or hosting a large pot-luck, and won't have enough pies of this caliber for everyone to have a piece, make sure you save the good pies for last (or at least selfishly reserve a piece for yourself).

If you only make one pie per year, I'd recommend my Pumpkin Pie over this one; it takes about the same amount of time, but has more depth of flavor.