Preheat oven to 350°F. Grease a 9-inch cake pan with cooking spray or butter. Line bottom with a round of parchment and grease the parchment.

Add egg whites to bowl of a stand mixer fitted with a whisk attachment. Whisk, starting at low and increasing speed to medium high until stiff peaks form.

While the whites are whisking, add the egg yolks, brown sugar, salt, and lemon zest to a large mixing bowl and stir until very smooth.

Pulse the pecans in a food processor until a sandy meal forms, but not so long that they turn into pecan butter. Stir the ground pecans into the egg yolk mixture until thoroughly combined.

Gently fold peaked egg whites into pecan mixture, taking care not to deflate them. Pour mixture into the prepared cake pan.

Bake for 35–40 minutes, until the top is browned and firm to touch and the center no longer wobbles.

Cool completely on a wire rack before removing from the pan. Wrap gently in foil and refrigerate for 8 hours or more before slicing and serving. Remove cake from the refrigerator an hour before serving and sprinkle it with confectioners’ sugar.