Step 1

Preheat oven to 350° and spray cookie sheet with non-stick spray.

Step 2

Beat together softened butter, brown sugar, and granulated sugar until smooth.

Step 3

Add in egg and vanilla extract and mix.

Step 4

Slowly add in flour, baking soda, baking powder, and salt.

Step 5

Gently blend ingredients together without over mixing.

Step 6

Using a spoon, gently stir in chocolate chunks and mini marshmallows.

Step 7

Using a cookie scoop, drop onto greased cookie sheet.

Step 8

Bake for about 11 minutes or until tops and edges of cookies are golden.

Step 9

Let cookies cool before moving to wire racks to cool completely.