Step 1

Preheat oven to 350 degrees and line a 9x9 with parchment paper.

Step 2

In a bowl, mix butter and peanut butter together until combined. Stir in brown sugar and granulated sugar, followed by the eggs and vanilla extract.

Step 3

Add in baking soda, salt, cinnamon, corn starch, and all-purpose flour, and mix until combined. Fold in Reeses and chocolate chips.

Step 4

Spread half of the dough evenly over the bottom of the pan. Set aside the rest of the dough.

Step 5

Spread marshmallow fluff on top of the dough, then press the remaining doup on top (it’s okay if some of the marshmallow fluff is showing).

Step 6

Bake for about 25 minutes, or until the top is lightly golden brown. Allow bars to cool for at least 30 minutes before cutting into them.

Step 7

Store remaining bars in an airtight container (they’re fine at room temperature, if it’s not too hot, for up to 4-5 days).