Ingredients
- 1 box brownie mix (18.4 oz / 520 g)
- 1/4 cup water (60 ml)
- 1/2 cup vegetable oil (120 ml)
- 2 large eggs
- 1 cup powdered sugar (120 g)
- 1/4 cup cocoa powder (30 g)
- 1/4 cup milk (60 ml)
- 1/2 cup mini marshmallows (45 g)
- 1/2 cup chopped walnuts or pecans (60 g)
Instructions
- Preheat oven to 350°F (175°C) and grease a 9×13 inch (23×33 cm) baking pan.
- In a large bowl, mix brownie mix, water, vegetable oil, and eggs until smooth.
- Pour half the batter into the pan and bake for 20 minutes until edges are set.
- Meanwhile, make the frosting: mix powdered sugar, cocoa powder, and milk until creamy.
- Spread frosting over the partially baked layer. Sprinkle marshmallows and nuts on top.
- Pour remaining brownie batter over the toppings and spread to cover evenly.
- Bake for another 25–30 minutes, until set and a toothpick comes out with moist crumbs.
- Let cool before slicing into squares.
Notes
- Swap walnuts with pecans or hazelnuts for a different flavor.
- Top with chocolate ganache for added indulgence.
- Use peanut butter chips or caramel bits instead of marshmallows.
- Add 1 tsp instant coffee to frosting for mocha flavor.
- Check doneness with a toothpick—look for moist crumbs, not a clean pick.
- Prep Time: 15 minutes
- Cook Time: 50 minutes
- Category: Dessert
- Method: Baking
- Cuisine: American
- Diet: Vegetarian
Nutrition
- Serving Size: 1 brownie
- Calories: 340
- Sugar: 28g
- Sodium: 210mg
- Fat: 18g
- Saturated Fat: 5g
- Unsaturated Fat: 11g
- Trans Fat: 0g
- Carbohydrates: 42g
- Fiber: 2g
- Protein: 3g
- Cholesterol: 35mg
