Heat the Oven: Start by preheating the oven to 350°F. Line an 8x8 inch baking pan with parchment paper, letting the edges hang over slightly. This makes lifting the brownies out much easier later.
Melt Butter and Mix Base: Place the butter in a microwave safe bowl and heat until melted. Stir in the sugar while the butter stays warm. Add the eggs one at a time, mixing well after each. Stir in vanilla until the mixture looks glossy and smooth.
Add Dry Ingredients: Sift flour, cocoa powder, and salt into the bowl. Fold gently until just combined. The batter should look thick and dark with no dry streaks left. Avoid overmixing to keep the brownies soft.
Bake the Brownies: Spread the batter evenly into the prepared pan. Smooth the top with a spatula. Bake until the center looks set but still soft. A toothpick should come out with moist crumbs, not dry.
Cool Completely: Let the brownies cool fully in the pan. This step matters since warm brownies can melt the topping and affect the texture.
Make the Ganache: Heat the cream until warm but not boiling. Pour it over the chocolate chips and let it sit briefly. Stir slowly until smooth and glossy.
Add the Topping: Pour the ganache over the cooled brownies and spread evenly. Sprinkle rainbow candy chips on top while the ganache stays soft. Chill until the topping firms up.
Slice and Serve: Lift the brownies out using the parchment. Cut into neat rectangles for that classic look.
