Follow these easy steps to create your Marshmallow Ghost Brownies:

1. Preheat the Oven: Start by preheating your oven to 350°F (175°C). Grease a 9×13-inch baking dish.

2. Melt the Butter: In a medium saucepan, melt the unsalted butter over low heat.

3. Mix Sugar and Eggs: Remove the saucepan from heat and stir in the granulated sugar. Add the eggs one at a time, mixing well after each addition. Then, add the vanilla extract.

4. Combine Dry Ingredients: In another bowl, whisk together the flour, cocoa powder, salt, and baking powder.

5. Merge Mixtures: Gradually add the dry mixture to the wet mixture, stirring until combined. Ensure there are no lumps.

6. Add Chocolate Chips: Fold in the semisweet chocolate chips, integrating them into the batter, which should be thick and fudgy.

7. Bake: Pour the brownie batter into the prepared baking dish, spreading it evenly. Bake for 30-35 minutes, or until a toothpick comes out with a few moist crumbs.

8. Cool: Remove the brownies from the oven and allow them to cool in the pan for 10-15 minutes.

9. Add Marshmallows: Once cooled slightly, sprinkle the mini marshmallows evenly over the top. Return to the oven for about 5 minutes to slightly melt the marshmallows.

10. Decorate: Drizzle chocolate icing or melted chocolate over the marshmallow layer. Use candy eyes to create the ghost faces on top.

11. Slice: Allow the brownies to cool completely before slicing them into squares.

By following these steps, you will create Marshmallow Ghost Brownies that are as fun to make as they are to eat!