Mix together the brownie mix, water, oil and egg in a bowl.
Line a cookie sheet with parchment paper or silicone baking mat and spray the paper with nonstick spray. Spread the batter over the parchment paper or mat to cover two thirds or three fourths of the pan.
Bake for 10 minutes. Rotate pan and bake another 10-15 minutes until firm.
Allow brownie crisps to cool completely before breaking into pieces.
Recipe by Mandy's Recipe Box at https://mandysrecipeboxblog.com/homemade-brownie-brittle/