Combine crumbs, pecans, the 3 tablespoons granulated sugar and margarine; press onto bottom of a 9-inch springform pan. Bake at 325 degrees F for 10 minutes.
Combine cream cheese and brown sugar, mixing at medium speed of electric mixer until well blended. Add eggs, one at a time, mixing well after each addition. Blend in chocolate and liqueur; pour over crust. Bake at 325 degrees F for 35 minutes.
Increase oven temperature to 425 degrees F.
Combine sour cream and the 2 tablespoons granulated sugar. Carefully spread over cheesecake. Bake at 425 degrees F for 10 minutes. Loosen cake from rim of pan. Cool before removing rim of pan. Chill.
Variation Substitute 2 tablespoons milk and 1/4 teaspoon almond extract for almond flavored liqueur.
