In a small pot on the stove, melt 2 sticks of butter. Set aside to cool slightly
When the butter has cooled slightly, add in the sugar and vanilla.
After the sugar is fully incorporated, add in the eggs.
Add the flour, baking powder, and salt to the butter mixture.
When the flour is almost mixed in, add in chopped chocolate and graham crackers.
Pour the batter into a parchment-lined square baking dish.
Place in the oven to cook for about 30-40 minutes. You want a toothpick inserted to come out clean!
In the last 2 minutes, add the mini marshmallows to the top.
Notes
I used an 8 by 8 dish to make my blondies because I like a thicker blondie. You can use a 9 by 13 if you would like! You'll get a thinner blondie and the cook time will be less! About like 25-30 minutes!