Preheat your oven to 350°F (175°C) and prepare an 8x8 inch baking pan by greasing it or lining it with parchment paper.

Mix ½ cup melted unsalted butter and 1 cup granulated sugar in a medium-sized bowl until smooth, then add 2 large eggs one at a time and 1 teaspoon vanilla extract.

Incorporate ⅓ cup cocoa powder, 1 cup flour, ½ teaspoon baking powder, and a pinch of salt into the wet mixture, mixing gently. Fold in ½ cup mini chocolate chips.

Pour the brownie batter into the prepared pan and bake for 20-25 minutes until a toothpick comes out with moist crumbs.

Cool the brownies in the pan for 10-15 minutes before transferring them to a wire rack to cool completely.

In a saucepan, combine ½ cup heavy cream, 2 tablespoons butter, and 1 teaspoon vanilla over low heat until the butter melts. Add 1 cup marshmallow fluff and mix until smooth.

Spread the warm marshmallow layer over the cooled brownies evenly.

Sprinkle 1 cup shredded coconut over the marshmallow layer, pressing it down gently.

Refrigerate for about 30 minutes to set the marshmallow topping, then slice into squares and serve.