Created by CookerKat on March 24, 2014
Step 1: Preheat oven to 350 degrees.
Step 2: In small bowl, mix flour, cornstarch, and baking soda.
Step 3: In large bowl, beat butter with sugars until light and fluffy. Beat in peanut butter. Add vanilla, egg, and egg yolk. Beat until smooth. Gradually beat in flour mixture. Chill for 2 hours.
Step 4: Roll into balls containing two teaspoons of dough each.
Step 5: Bake for 8-10 minutes until the edges are set.
Step 6: Cool on pans for 5 minutes.
Step 7: Gently press indentations into the center of each cookie. Cool on pan two more minutes. Place on wire rack to cool completely.
Step 8: Place marshmallow creme in medium bowl. Microwave on high for 30 seconds. Stir. Microwave on high for 30 more seconds. Stir until smooth. Carefully spoon hot marshmallow over cookie indentations. Cool completely