Begin by melting 1 cup of unsalted butter in a medium saucepan over low heat, stirring until smooth. Once melted, remove from heat and mix in 2 cups of granulated sugar until well combined. Let the mixture cool for about 10 minutes, then add 4 large eggs one at a time, stirring vigorously after each addition. Finish by stirring in 1 teaspoon of vanilla extract.

In a separate bowl, whisk together 1 cup of all-purpose flour, 1 cup of unsweetened cocoa powder, ½ teaspoon of baking powder, and ½ teaspoon of salt.

Gradually add the dry ingredient mixture to the wet ingredients, gently folding with a spatula until just combined.

Preheat your oven to 350°F (175°C) and grease a 9x13 inch baking pan or line it with parchment paper. Pour the brownie batter into the prepared pan, spreading it evenly. Bake for 25-30 minutes, or until a toothpick inserted in the center comes out with moist crumbs.

Once baked, remove the pan from the oven and let the brownies cool in the pan on a wire rack for at least 30 minutes.

While the brownies cool, prepare your witch hats by dipping the tops of 12 chocolate ice cream cones in melted chocolate. Roll the dipped edges in colorful Halloween-themed sprinkles.

In a mixing bowl, combine 2 cups of powdered sugar, ¼ cup of milk, and a few drops of green food coloring. Mix until smooth and fluffy.

Spread the green frosting generously over the cooled brownies, creating a fun base for your witch hats.

Finally, take your decorated ice cream cones and place one upside-down on top of each frosted brownie. Press them gently into the frosting to secure.