Pi Day 2016 - Sweet Potato Pie with Marshmallow Meringue in a Gingerbread Crust

This pie feels completely out of season, and it is, but it was an idea I couldn't get out of my head for Pi Day 2016. This would be the PERFECT pie for Thanksgiving, and I suppose for spring I should have been thinking lemon meringue or something with cream cheese.

It starts with Dominique Ansel's gingerbread crust, which I did not end up caring for much. It's rather more like a soft ginger cookie than a pie crust, making it increasingly difficult to work with, but it did have good flavor. I've had it on my mind ever since I first came across it. Overall it is more subtle than I expected, which makes it more versatile (but I still probably won't make it again, maybe just add ginger to a more tried and tested pie dough recipe.)

The pie itself is a version of a popular pie idea - taking what is normally a Thanksgiving side dish in the United States (sweet potatoes or yams with marshmallows on top) and making a pie version. I used the recipe from a cookbook I have at home, The Southern Pie Book, but it is basically the Southern Living recipe which I will post below. I had to bake the pie 15 minutes longer to get it to set in the middle. I thought it was okay but overall very sweet. And as Mr. JennyBakes pointed out, if you have this as a pie then you won't have it as a side dish, and having sweet potato casserole as a side dish is like a way to sneak dessert into dinner.

Dominique Ansel's Gingerbread Pie Crust
(as seen on Eater, where the pictured pie crust is quite darker than the one I made)

(Makes 2 pie crusts)

Ingredients:
½ cup plus 1 tbsp light brown sugar
2/3 stick unsalted butter, softened
3 tbsp lemon juice
1 tbsp milk
½ tsp vanilla extract
1¾ cups all purpose flour
1 tsp ground cinnamon
1 tsp ground ginger
Pinch nutmeg
2 tbsp fresh ginger, grated
2 tbsp cornstarch
Pinch Maldon sea salt

Method:

1. In a stand mixer fitted with a paddle attachment, cream together butter and sugar on medium-low speed until light and fluffy, about 3 minutes. While continuing to mix, stream in lemon juice, followed by milk and vanilla, until evenly combined.
2. In a bowl, whisk together the flour, cinnamon, ground ginger, nutmeg, grated ginger, cornstarch and salt until combined. With the mixer on medium-low speed, add in one-third of the dry ingredient mixture until evenly combined. Repeat with the next third of the dry ingredients, then the final third.
3. Scrape down the sides of the bowl, and transfer the dough onto a sheet of plastic wrap. Form the dough into a rectangle no more than ½ inch thick, wrap in the plastic wrap and chill in the refrigerator for at least 1-2 hours.
4. Remove the dough from the fridge. Divide the dough in half (this recipe yields two pie crusts, so you can keep one half wrapped in plastic wrap in the fridge). On a lightly floured surface, roll out the dough into a 14-inch round. Transfer to a pie tin, gently pressing down into the corners and up the sides. Trim away excess dough using a paring knife, leaving a 1-inch overhang around the edge. Fold the edges under, then form a fluted edge around the rim with your fingers. Lightly dock the bottom surface of the dough with a fork. Chill or freeze the pie shell in the pie pan until ready to bake.
5. Preheat the oven to 350F.
6. Line the pie shell with a coffee filter and fill with rice or dried beans to blind bake the crust. Bake in the oven for 14-16 minutes, until the bottom of the pie crust is just lightly baked.
7. Remove from oven and discard the coffee filter and rice/beans. Return the crust to the oven and bake until golden brown, approximately 4 more minutes. Remove from oven and let cool.

Sweet Potato Pie with Marshmallow Meringue
(recipe from The Southern Pie Book, originally from Southern Living) 

FILLING:
 

1/4 cup butter, melted

1 cup sugar

1/4 teaspoon salt

3 large eggs

3 cups lightly packed, cooked, mashed sweet potatoes (about 2 1/2 lb. sweet potatoes)

1 cup half-and-half

1 tablespoon lemon zest

3 tablespoons lemon juice

1/4 teaspoon ground nutmeg 

 

MARSHMALLOW MERINGUE: 

 

3 egg whites

1/2 teaspoon vanilla extract

1/8 teaspoon salt

1/4 cup sugar

1 (7-oz.) jar marshmallow crème 

 

Preparation

1. Whisk together egg yolk and cream; brush bottom and sides of crust with yolk mixture. Bake 6 to 8 more minutes or until crust is golden. Transfer to a wire rack, and cool. Reduce oven temperature to 350° F.
2. Prepare filling: Stir together melted butter, 1 cup sugar, and next 2 ingredients in a large bowl until mixture is well blended. Add sweet potatoes and next 4 ingredients; stir until mixture is well blended. Pour sweet potato mixture into prepared piecrust. (Pie will be very full.)
3. Bake at 350° for 50 to 55 minutes or until a knife inserted in center comes out clean, shielding with aluminum foil to prevent excessive browning. Preheat oven to 400° F.
4. Prepare meringue: Beat egg whites and next 2 ingredients at high speed with a heavy-duty electric stand mixer until foamy. Gradually add sugar, 1 Tbsp. at a time, beating until stiff peaks form.
5. Beat one-fourth of marshmallow crème into egg white mixture; repeat 3 times with remaining marshmallow crème, beating until smooth (about 1 minute). Spread over pie.
6. Bake at 400° for 6 to 7 minutes or until meringue is lightly browned.