PREP: Position a rack in the center of the oven and preheat the oven to 350ºF. Spray an 8x8 square baking pan with cooking spray and line with parchment paper, set aside.

CRUMBS: Melt the butter in a medium bowl. Add the graham cracker crumbs, ground pecans, sugar, cinnamon, nutmeg, and stir to combine. Make sure all the crumbs are moistened in the butter. Press the crumbs into the bottom of the baking pan and bake for 10 minutes. Remove from oven, leave the oven on.

FILLING: In the bowl of an electric mixer fitted with the whisk attachment, whisk the yolks for 2 minutes. Add the vanilla extract and condensed milk and continue to whisk for another 2 minutes. Stop the mixer, scrape down the sides, add the sour cream and lemon zest. With the mixer on low, drizzle in the lemon juice. Let the mixer run for 2 minutes once added. The mixture will visibly look slightly thicker when done.

BAKE: Pour the filling into the crust and bake for 17 minutes. Cool completely on rack. Filling will set as it cools. When completely cooled, refrigerate for at least 2 hours. Slice and serve chilled.