Preheat the oven to 355 degrees F (180 degrees C). Place a foil in the 8-inch square pan. Lightly grease the corners, set aside.

In a medium-sized bowl, add the chocolate and butter for the brownies. Microwave for 1 minute at 50 percent power and stir once in between, until the chocolate and butter melt. Whisk the granulated and brown sugars along with eggs and vanilla extract. In a separate bowl, add baking powder, flour, chocolate chips, and salt. Gently mix all the ingredients into the chocolate mixture with a spatula until evenly combined.

Pour the batter in the pan and bake for 25-30 minutes. Make sure a thin-pointed knife or toothpick inserted comes out clean or with few crumbs. Remove the brownies from the oven and allow it to cool down completely.

You can use an electric mixer to blend cocoa powder, butter, and salt on medium speed for about 2-3 minutes. Scrape the sides of the bowl with a spatula and add powdered sugar. Mix on low speed to form a thick frosting.

Add milk and vanilla extract, starting with a few tablespoons and adding more on the basis of the consistency. Increase the mixer speed to medium-high, beating until smooth and fluffy.

Now, spread the frosting on the brownies. You can serve the brownies in a bowl with vanilla ice-cream or your preferred choice of sprinkles.