Preheat the oven to 425 degrees F. Butter six 6-ounce ramekins and then spray them with cooking spray; line the bottoms with rounds of parchment. Put the ramekins on a baking sheet and put in the oven to preheat.
Assemble the ingredients from the box for making the cake-like brownies, but separate the eggs. Whip the egg whites to stiff peaks in a bowl with a mixer. In a separate bowl, add the brownie mix and mix in the water, oil and egg yolks. Mix in 1/2 cup of the whipped egg whites to thin the brownie batter. Gently fold in the remaining egg whites.
Working quickly, evenly divide the batter among the preheated ramekins, filling them about halfway full (about 1/2 cup per ramekin). Bake until the tops of the cakes are set but the centers are still a little soft to the touch, about 14 minutes. Let sit for 5 minutes.
Run an offset spatula around the edge of each cake and invert onto separate serving plates. Drizzle the plates with Sunny's 1-2-3 Berry Sauce, top each cake with a spoonful of whipped cream and garnish with a mint sprig.
Sunny's 1-2-3 Berry Sauce:
In a saucepot on medium-high heat, add the berries, sugar and lemon juice. Cook, stirring, until the berries begin to break down, the sugar dissolves and the liquid reduces slightly, 8 to 10 minutes. Serve warm or chilled.