Heat oven to 350°F. Generously butter bottom and sides of 2 (6-oz) custard cups with softened butter. In small bowl, stir together topping and cinnamon. Divide between custard cups. Sprinkle with walnuts. Place frozen biscuit in each cup. Sprinkle each biscuit with 1/2 teaspoon sugar.
Bake 23 to 27 minutes or until golden brown and biscuits are no longer doughy. Immediately run sharp knife around edge of cup; turn each upside down onto serving plate. Slowly lift custard cup from biscuit, releasing biscuit onto plate. Spread any topping remaining in cup over biscuit. Cool 5 minutes before serving.