MAPLE BUTTERMILK CUSTARD PIE

via food & wine / PHOTO © ANNA WATSON CARL

My favorite baking duo, sisters Emily and Melissa Elsen, of Four & Twenty Blackbirds in Brooklyn, New York make, hands down, some of the best pies I've ever eaten. The standard classics in their cookbook, The Four & Twenty Blackbirds Pie Book, make me feel all warm and fuzzy but the uncommon pies with their unusual pairings and flavor profiles inspire me to bake. 

As a Southerner I'm a huge fan of buttermilk pie but this recipe for Maple Buttermilk Custard Pie takes the slice! In a weird way the flavor reminds me of my grandma's homemade biscuits - piping hot from the oven - and topped with a swirl of melted butter and Winesett honey (orange blossom). Yum. This pie is worth every bit of time it takes to bake it. 

Maple Buttermilk Custard Pie
Cornmeal Crust for a 9-inch single-crust pie, partially pre-baked (recipe below)
1 tablespoon unbleached all-purpose flour
1 tablespoon stone-ground white cornmeal
¼ cup packed light brown sugar
½ teaspoon kosher salt
5 tablespoons unsalted butter, melted
1 teaspoon vanilla paste (or vanilla extract)
1 cup sour cream
3 large eggs
1 large egg yolk
¾ cup maple syrup (preferably Grade B)
1 cup buttermilk

1. Position a rack in the center of the oven and preheat the oven to 325°F. Place the prebaked pie shell on a rimmed baking sheet.
2. In a large bowl, mix together the flour, cornmeal, brown sugar, salt, and melted butter. Add the vanilla paste (or vanilla extract) and the sour cream and stir until smooth. Add the eggs and egg yolk one at a time, blending well after each addition. Add the maple syrup and buttermilk and mix until smooth.
3. Strain the filling through a fine-mesh sieve directly into the pie shell, or strain it into a separate bowl and then pour it into the shell. (FYI: I was left with about 1/3 cup of filling that would not make it through the strainer.) 
4. Bake on the middle rack of the oven for 45 to 55 minutes, rotating 180 degrees when the edges start to set, 30 to 35 minutes through baking.
5. The pie is finished when the edges are set and puffed slightly and the center is no longer liquid but still quite wobbly.
6. Be careful not to over-bake or the custard can separate; the filling will continue to cook and set after the pie is removed from the oven.
7. Allow to cool completely on a wire rack, 2 to 3 hours. Serve slightly warm, at room temperature, or cool. The pie will keep refrigerated for 2 days or at room temperature for 1 day.

Cornmeal Crust (for a single-crust pie)

1 cup unbleached all-purpose flour
¼ cup stone-ground cornmeal
½ teaspoon kosher salt
1½ teaspoons granulated sugar
¼ pound (1 stick) cold unsalted butter, cut into ½-inch pieces
½ cup cold water
2 tablespoons cider vinegar
½ cup ice

1. Stir the flour, cornmeal, salt, and sugar together in a large bowl. Add the butter pieces and coat with the flour mixture using a spatula. With a pastry blender (or using your fingers like we did), cut the butter into the flour mixture, working quickly until mostly pea-size pieces of butter remain (a few larger pieces are okay; be careful not to over blend). 
2. Combine the 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, and 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.
3. Shape the dough into a flat disc, wrap in plastic, and refrigerate for at least 1 hour, preferably overnight, to give the crust time to mellow. Wrapped tightly, the dough can be refrigerated for 3 days or frozen for 1 month.

How to partially pre-bake it:

1. Once dough has been chilled in the refrigerator for at least 30 minutes, roll it out and shape it into a 9-inch pie plate. Use a fork to prick all over the bottom and sides, 15 to 20 times. Place the shaped crust in the freezer. Position the oven racks in the bottom and center positions, place a rimmed baking sheet on the lowest rack, and preheat the oven to 425°F.
2. When the crust is frozen solid (about 10 minutes), line it tightly with a piece or two of aluminum foil. Make sure the edges are completely covered and there are no gaps between the foil and the crust.
3. Pour pie weights or dried beans into the pan and spread them so they are concentrated more around the edge of the shell than in the center. Place the pan on the preheated baking sheet and bake for 20 minutes, until crimped edges are set but not browned.
4. Remove the pan and the baking sheet from the oven, lift out the foil and pie weights, and let the crust cool for a minute. Use a pastry brush to coat the bottom and sides with a thin layer of egg white glaze (1 egg white whisked with 1 teaspoon of water) to moisture-proof the crust. Return the pan, on the baking sheet, to the oven’s middle rack and continue baking for 3 more minutes. Remove and cool completely before filling.