Preheat the oven to 350 F. Line a 12 cup muffin pan with paper liners. In a large bowl, whisk together brown sugar, melted butter, eggs, and vanilla extract until smooth.
Add in the flour, salt, and baking powder, and mix until combined. Fold in the chocolate chips, mini marshmallows, and crushed graham crackers.
Evenly divide the mixture between a paper lined muffin pan. Bake for 12-15 minutes.