Place water and Krusteaz Professional Fudge Brownie Mix in mixer bowl. Using a whisk, mix until smooth. If using Ready to Bake Brownie Batter, pour on to 1/2 sheet pan and spread with a spatula.
Scale batter into greased full sheet pan. Omit step if using Ready to Bake Brownie Batter.
For convection oven, bake at 300°F 27-32 minutes; for standard oven, bake at 350°F 30-35 minutes. Bake Ready to Bake Brownie Batter according to instructions.
Cut into desired shape and plate.
Pipe caramel mousse on brownie then stack with another brownie. Pipe with caramel mousse.
Top with a third brownie. Pipe caramel mousse on brownie. Add a garnish, if desired.