Ingredients
Equipment
Method
Bake the brownies
- Bake the brownie mix in a 9x13 pan according to package directions, then cool completely. Keep the top surface dry and fully cooled so the ice cream layer won’t melt or slip.
Build the frozen layers
- Fold the rainbow sprinkles into the softened cake batter or birthday cake ice cream until evenly dotted. Use a gentle fold so the sprinkles spread through the ice cream rather than clump.
- Spread the sprinkle ice cream over the cooled brownies in a thick, even layer. Press lightly to level the surface for clean slices later.
- Drizzle the hot fudge sauce over the top and swirl with a knife. Create visible ribbon streaks without fully mixing them into the ice cream.
- Freeze for 6 hours until completely firm. The edges should look set and the center should hold shape when you gently press the surface.
- Cover with the whipped topping and shower generously with rainbow sprinkles. Add extra sprinkles while the topping is fresh so they adhere.
- Freeze for 2 more hours before slicing. Let the cake sit at room temperature for 5 minutes for easier cutting and neater layers.
Notes
Pro tip: cool the brownies fully before adding ice cream—if they’re warm, the layers will slide and the fudge ribbon won’t stay distinct. Refrigerate leftovers only briefly; store this cake covered in the freezer for up to 2 weeks (freeze yes). For a lighter option, use low-fat whipped topping and a reduced-sugar hot fudge sauce to cut calories while keeping the layered texture.