Mix together Graham crackers, sugar and melted butter and line the bottom of a 9 inch spring-form pan. Bake 10 minutes at 350F
Blend together cream cheese, dark brown sugar and eggs, added one at a time. Blend in sour cream, vanilla and ground pecans.
Bake 1 hr at 350F
Mix together topping and spread over top of cake.
After cooling cut into 16 pieces. Top each piece with pecan.