Preheat oven to 350 F (175 C). Butter and flour 9 inch (23 cm) spring form pan. Using an electric mixer,
cream 3/4 cup butter and granulated sugar until light. Add the eggs and vanilla and
beat until fluffy. In a separate bowl combine the flour, baking powder, baking soda and salt. Add the dry ingredients to the egg mixture in 3 parts, alternating with the sour
cream.
Mix well after each addition, scraping the bowl as necessary.
Dissolve the coffee in the hot water. Remove 1/3 of the batter to another bowl and add the coffee mixture. Combine the
brown sugar, walnuts and 1/8 cup melted butter. Spread half of the remaining batter in the pre
pared pan. Cover with the coffee-flavored batter and then the
brown sugar-walnut mixture. Top with the remaining batter.