Place whipping cream in a small non-aluminum saucepan; cook over medium heat, stirring constantly, 5 minutes or until mixture is reduced in volume to 2 tablespoons. Remove from heat; stir in crème de framboise and broken chocolate.
Return mixture to low heat, stirring until chocolate melts. Add butter; beat with a wire whisk until smooth. Pour mixture into an 8-inch square baking pan. Chill until firm. Using a teaspoon, scoop up chocolate mixture, and shape into 1/2-inch balls. Chill.
Sift together cocoa and sugar; roll each ball in cocoa mixture until well coated. Store in airtight containers in refrigerator. Let stand at room temperature 20 minutes before serving.
Note: Grand Marnier, Kahlua, crème de menthe, Amaretto, or a dark rum may be substituted for raspberry liqueur.