Beat cheese until light and fluffy. Add sugar and beat again. Add eggs one at a time; beating after each. Add remaining ingredients. Mix well. Pour into crust and bake at 450 for 15 minutes with a pan of water on the bottom rack of oven. Reduce temp to 250 and bake 1-1/2 hours longer. Combine 6 T. butter with 1 cup firmly packed brown sugar and one cup chopped walnuts. Return to oven for 10 minutes. Remove. Run knife around edge and cool thoroughly. Chill.