Chocolate-on-Chocolate Tart with Maple Almonds

Pulse cocoa powder, sugar, salt, and 1 1/4 cups flour in a food processor to combine. Add butter; pulse until mixture resembles coarse meal. Beat egg yolk and 3 tablespoons ice water in a small bowl; add to flour mixture and pulse until dough just comes together. Form into a 3/4"-thick disk, wrap tightly in plastic, and chill until firm, at least 2 hours. Preheat oven to 350 °F. Roll out dough on a lightly floured surface to a 12" round. Transfer to tart pan; lift up edges and let dough slump down into pan, then gently press into edge of pan. Trim dough, leaving about a 1" overhang. Fold in overhang; press to adhere. Prick bottom with a fork. Chill in freezer 15 minutes. Line pie with parchment paper or heavy-duty foil, leaving a 1 1/2" overhang. Fill with pie weights or dried beans. Place on a rimmed baking sheet and bake until crust is dry around the edges, about 30 minutes. Remove parchment and weights and bake until crust is firm and looks dry all over, 5 –10 minutes longer. Transfer pan to a wire rack and let crust cool. DO AHEAD: Dough can be made 2 days ahead; keep chilled. Crust can be baked 1 day ahead; store tightly wrapped at room temperature.