Prepare Brownies: Prepare your brownie base according to the package instructions or your favorite homemade recipe. Bake in a preheated oven at 350°F (175°C) for 25-30 minutes, or until a toothpick inserted into the center comes out with moist crumbs. Let cool completely.

Mousse Prep: Chop the dark chocolate into small pieces. Bloom gelatin by sprinkling it over cold water, letting it sit for 5 minutes.

Heat Cream: Gently heat half a cup of heavy cream until it boils. Pour hot cream over dark chocolate and let sit for a minute. Stir until smooth.

Combine Gelatin: Dissolve the bloomed gelatin in warm water, then stir into the chocolate cream mixture until combined. Allow to cool.

Whip Cream: In a separate bowl, whip remaining cream until soft peaks form, about 2-3 minutes. Avoid overwhipping.

Fold Mixtures: Gently fold half of the whipped cream into the cooled chocolate mixture. Add the remaining whipped cream and fold until combined.

Chill Mousse: Spread chocolate mousse over brownies. Cover with plastic wrap and refrigerate for at least 1-2 hours.

Garnish Optional: Once set, remove brownies from the fridge and garnish with grated white chocolate, fresh berries, and mint leaves.