Step 1

Preheat oven to 350° F. Grease 8-inch-square baking pan.

Step 2

Melt butter and 1/3 cup morsels in medium saucepan over medium heatstirring constantlyuntil melted (about 4 to 5 minutes). Remove from heat. Stir in sugarflournutseggs and vanilla extract until well mixed. Spread into prepared baking pan.

Step 3

Bake for 25 to 30 minutes or until sides of bars begin to pull away from edges of pan. Sprinkle with marshmallows. Continue baking for 3 minutes.

Step 4

Combine 1/2 cup morsels and vegetable shortening in smallmicrowave-safe bowl. Microwave on HIGH for 1 minutestirring occasionallyuntil melted. Drizzle bars with chocolate. Cool completely in pan on wire rack. Cut into bars.