In a large skillet melt butter; stir in brown sugar until melted. Cook, stirring frequently, over medium heat until boiling. Reduce heat to medium-low. Cook and stir for 1 minute. Remove from heat. Add raspberries, nuts, and lemon peel; stir very gently to coat.
Scoop ice cream and/or sorbet into eight small dessert cups. Top with raspberry mixture. Serve immediately. Makes 8 servings.