Notes: If the nut flour is not available, use 1 cup pecans: bake in a 350° oven until golden under skins, about 10 minutes, then whirl in a food processor until finely ground.
Butter and flour a 9-inch cake pan with a removable rim. In a bowl, stir together all-purpose flour, pecan flour, baking powder, and salt.
In a small bowl, mix egg yolks, maple syrup, pecan oil, and brandy. Pour into flour mixture; stir to combine.
In a large bowl, with a mixer, beat egg whites until soft peaks form. Beat in sugar, a tablespoon at a time, and continue to beat until glossy, about 2 minutes. Stir a quarter of the egg-white mixture into yolk mixture. Scrape into remaining egg-white mixture and fold in gently.
Pour batter into prepared pan. Bake in a 350° oven until cake springs back when lightly pressed in the center, 30 to 35 minutes. Transfer in pan to a rack and let cool about 1 hour.
Remove pan rim. Cut cake in half horizontally and place bottom layer on a cake plate. Spread half the maple-cream cheese frosting on bottom layer; top with remaining layer. Spread remaining frosting over top (leave sides bare). Sprinkle with chopped pecans.