Start by preheating your oven to 350°F (175°C). Grease a 9x9 inch baking dish and set it aside. In a mixing bowl, combine the melted butter and granulated sugar, whisking until smooth. Then, incorporate the eggs one at a time, adding the vanilla extract last.
Next, sift in the cocoa powder and flour, gently folding until just combined. Pour the batter into your prepared dish and bake for about 25-30 minutes or until a toothpick comes out with a few moist crumbs.
While the brownies are cooling, make the strawberry mousse. Blend the fresh strawberries into a smooth puree. In another bowl, whip the heavy cream and powdered sugar until soft peaks form, then gently fold in the strawberry puree until well combined.
Once the brownies are completely cool, spread the strawberry mousse evenly over the top. Chill in the refrigerator for at least an hour to set, then slice and serve. Enjoy your delicious strawberry mousse brownies!
Notes
This dessert is best served chilled, and you can garnish it with extra strawberries or a drizzle of chocolate if you like!