White-Chocolate Mousse and Brownie Eggs

Heat oven to 350 °F. Double up 24 Reynolds foil egg-shaped baking cups so you have 12 nested cups. Coat with nonstick spray. Place on a rimmed baking sheet. Make Brownies: Prepare brownie mix as directed on box for fudgy brownies. Divide batter among cups (about 3 Tbsp each). Bake 15 to 20 minutes until a toothpick inserted in centers comes out clean. Cool completely on a wire rack. Make Mousse: Heat 1 ⁄2 cup cream and the sugar in a medium saucepan over medium-low heat, stirring until sugar dissolves. Add chocolate; stir until melted. Scrape into a medium bowl and let cool. Beat remaining 1 cup cream with mixer on high speed until soft peaks form when beaters are lifted. Stir a large dollop into chocolate mixture, then fold in remaining. Remove 3 ⁄4 cup mousse. Divide among as many small bowls as colors you plan to use. Tint each a color. Spoon into small ziptop bags, press out air, then seal bags. Spoon remaining mousse on brownies (about 2 rounded Tbsp each). Spread to edge. Cut tip off 1 corner of each bag; pipe designs on eggs. Refrigerate at least 1 hour before removing foil to serve.