Stack the tortillas and wrap in a piece of foil; grill over medium-low heat about 5 minutes or until warm and pliable, turning packet once. [Or, wrap the tortilla stack in microwave-safe paper towels instead of foil; microwave on 100 percent power (high) for 20 to 40 seconds or until tortillas are warm and pliable.]
Sprinkle 1/4 cup each of the chocolate pieces and the raspberries in the center of each tortilla; fold in sides and roll up. Brush burritos with half of the melted butter. Grill burritos on the rack of an uncovered grill directly over medium-low heat about 3 minutes or until the tortillas begin to show grill marks and the chocolate is melted, turning once. Transfer to a serving platter. Brush tortillas with remaining melted butter. In a small bowl combine the sugar and cinnamon; sprinkle over the burritos. Serve immediately. Makes 4 servings.