1) Prepare the pan and oven

Set your oven to 350°F. Line an 8×8-inch baking pan with parchment paper, leaving a little overhang so you can lift the brownies out easily later.

2) Build the brownie base

Melt the butter in a medium saucepan over low heat. Once it melts, stir in the granulated sugar, brown sugar, cocoa powder, and salt until the mixture looks smooth and fully combined.

Pour the warm mixture into a large bowl and whisk in the vanilla. Add the eggs one at a time, beating well after each addition until the batter looks thick, glossy, and silky.

Fold in the flour and cornstarch just until no dry streaks remain. Do not overmix — that keeps the brownies fudgy instead of tough.

3) Bake the brownies

Spread the batter evenly into the prepared pan. Bake for 20–22 minutes, or until the edges look set and the center still has a slight wobble.

Let the brownies cool completely in the pan. For the cleanest finish, invert them after cooling and peel off the parchment paper.

4) Make the ganache

Warm the heavy cream in the microwave for about 30 seconds, just until hot. Pour it over the chopped chocolate and let it sit for 1 minute.

Add the pinch of salt, then stir until the mixture becomes smooth, shiny, and pourable. Spread the ganache over the cooled brownie layer.

5) Add the rainbow chips and chill

Sprinkle the rainbow candy-coated chocolate chips over the ganache while it is still soft. Then chill the brownies for 1–2 hours, or until the topping is set.

 

Use a sharp knife to slice, wiping the blade between cuts for neat edges.