Let pie crust stand according to package directions. Unroll pie crust; place into a 9-inch pie plate. Fold pie crust under and flute edges.
In a medium mixing bowl, beat the 3 tablespoons butter with an electric mixer on medium to high speed for 30 seconds. Add the 3/4 cup sugar, cocoa powder and salt. Beat until combined, scraping sides of bowl as needed. Beat in two eggs and 1/2 teaspoon vanilla. Pour filling into crust. Cover edge of pie with foil to prevent overbrowning.
Bake in a 350° oven for 20 minutes or until top of filling is set. Remove pie from oven but leave oven turned on.
In a medium mixing bowl, lightly beat two eggs with a fork. Stir in the 1/2 cup sugar, the corn syrup, flour, the 1 tablespoon melted butter and the 1 teaspoon vanilla; mix well. Stir in the pecans.
Carefully spoon the topping over the filling. Return pie to oven. Bake for 25 minutes. Remove foil. Bake for 15 to 20 minutes more or until a knife inserted near the center comes out clean. Cool on a wire rack. Cover and chill within 2 hours. Makes 8 servings.