Preheat your oven to 350°F (175°C). Grease an 8x8-inch baking pan with butter or line it with parchment paper.

Combine ½ cup of melted unsalted butter with 1 cup of granulated sugar. Stir until smooth, about 2-3 minutes. Add 2 large eggs and 1 teaspoon of vanilla extract, then beat until blended.

Sift in ⅓ cup of cocoa powder, ½ cup of all-purpose flour, ½ teaspoon of salt, and ½ teaspoon of baking powder. Gently fold together until just combined.

Fold in ½ cup of mini chocolate chips and pour the batter into the prepared baking pan, spreading evenly.

Bake for 20-25 minutes and check for doneness using a toothpick.

Cool completely in the pan on a wire rack for 30-45 minutes.

In a saucepan over low heat, combine ½ cup of heavy cream, 2 tablespoons of unsalted butter, and 1 teaspoon of vanilla extract. Stir until melted, then add 1 cup of marshmallow fluff and whisk until smooth.

Spread the marshmallow mixture on top of the brownies, then sprinkle with 1 cup of shredded coconut, pressing down lightly.

Chill in the refrigerator for 30 minutes before slicing into squares.