Put oven rack in middle position and preheat oven to 350°F (180 C).

Stir together crumbs, butter, and sugar and press on bottom and up side of a 9-inch pie plate (1-quart capacity). Bake until crisp, about 15 minutes, and cool on a rack.

Whisk together sugar, cornstarch, salt, and yolks in a 3-quart heavy saucepan until combined well, then add milk in a stream, whisking. Bring to a boil over moderate heat, whisking, then reduce heat and simmer, whisking, 1 minute (filling will be thick).

Force filling through a fine-mesh sieve into a bowl, then whisk in chocolates, butter, and vanilla. 5. Cover surface of filling with a buttered round of wax paper and cool completely, about 2 hours.

Spoon filling into crust and chill pie, loosely covered, at least 6 hours.

Just before serving, beat cream with sugar and vanilla in a bowl using an electric mixer until it just holds stiff peaks, then spoon on top of pie.

Grate some chocolate and top with berries.