Preheat the oven to 350°. Mix together the crackers and butter and use the mixture to line a 9 inch springform pan. Bake for about 10 minutes. Set aside to cool. Reduce the oven to 325 °.
With an electric mixer, beat together until fluffy the cream cheese, eggs, and 1/4 cup sour cream. Add the lemon juice, onion, Old Bay seasoning, Tabasco, and black pepper. Stir in the crabmeat and mix well. Pour into the cooled crust and bake 50 minutes until the cake sets. Remove from the oven. Run a knife around the edge of the cake, loosening it from the pan. Cool on a wire rack. Remove the sides of the pan. Spread the cake with the sour cream.