1 - Line an 8-inch-square baking pan with wax paper or foil, and coat with non-stick spray.

2 - Pour ½ cup of the miniature marshmallows into the bottom of the lined baking dish.

3 - In a microwave-safe bowl, combine the chocolate chips and peanut butter.

4 - Microwave the chocolate mixture in 20-second intervals, stirring in between each interval, until the chocolate is melted.

5 - Add the vanilla extract and stir well, until smooth.