Brown Butter Sweet Potato Pie

To prepare crust: Combine all-purpose flour, whole-wheat flour and salt in a food processor; pulse several times to blend. Add butter and process until the mixture resembles coarse meal, 8 to 10 seconds. Add yogurt and pulse until combined. With the motor running, add ice water, 1 tablespoon at a time, until the dough holds together without being sticky or crumbly. Divide the dough into 2 equal portions, shape into disks, and wrap each in plastic wrap. Refrigerate until firm, about 30 minutes.

To prepare and assemble pie: Position racks in center and lower third of oven; preheat to 425°F. Line a rimmed baking sheet with parchment paper or a silicone baking mat.

Remove 1 disk from the refrigerator and let stand at room temperature for 10 minutes before rolling. (Reserve the remaining disk for another use.) Roll pie crust into a 13-inch circle, about 1/8 inch thick, on a lightly floured surface. Transfer to a 9-inch pie pan. Fold the overhanging pastry under itself along the rim of the pan. Press a fork around the edge or flute it by pinching with your finger and thumb to crimp the folded dough. Crumple a piece of parchment paper, then lay it out flat over the pastry. Fill with pie weights, dried beans or uncooked rice.

Place sweet potatoes on the prepared baking sheet and prick them in several places with a fork. Set the sweet potatoes on the center rack and the pie crust on the lower rack. Bake for 20 minutes. Remove the pie crust from the oven, take out the paper and weights and let cool. Reduce oven temperature to 350° and continue baking the sweet potatoes until soft and tender, about 30 minutes more.

Meanwhile, melt butter in a small pan over medium heat. Cook until lightly browned, about 3 minutes. Remove from heat and add cardamom, cinnamon, salt and white pepper.

When the sweet potatoes are cool enough to handle, peel them and mash with a potato masher in a large bowl or the bowl of a stand mixer. Beat with an electric mixer or the whisk attachment at medium speed until completely smooth, about 2 minutes. Add eggs and beat until well incorporated. Add the spiced butter and any browned bits, condensed milk, lemon zest and lemon juice and beat until incorporated. Pour the mixture into the crust.

Bake until the pie is puffed and a toothpick inserted into the filling comes out clean, about 45 minutes. (If the exposed edges of the crust start to brown too quickly, cover with strips of foil for the last 15 minutes of baking.) Transfer to a rack and let cool, at least 1 hour.