In a medium saucepan over low heat, combine 1/2 cup of unsalted butter and 1 cup of semi-sweet chocolate chips. Stir gently until smooth and glossy, about 5-7 minutes.

In a large mixing bowl, combine the melted butter and chocolate with 1 cup of granulated sugar. Whisk until smooth, then add 2 large eggs one at a time, mixing thoroughly after each addition. Stir in 1 teaspoon of vanilla extract.

In another bowl, whisk together 1 cup of all-purpose flour, 1/3 cup of unsweetened cocoa powder, and 1/4 teaspoon of salt. Gradually fold this dry mixture into the wet batter until just combined.

Preheat your oven to 350°F (175°C) and grease a 9x9 inch baking dish. Pour the brownie batter into the prepared dish, spreading it evenly. Bake for 20-25 minutes, testing for doneness with a toothpick.

Once baked, let the brownies cool in the baking dish for 10-15 minutes, then transfer to a wire rack to cool completely. Frost generously with chocolate frosting and decorate with chocolate chips and assorted candies.