Preheat your oven to 350°F (175°C). Line your baking pan with parchment paper.

Cream together the unsalted butter, sugar, and vanilla extract until light and fluffy, about 3-5 minutes. Add in the eggs one at a time.

In a separate bowl, combine the all-purpose flour, unsweetened cocoa powder, and salt. Gently fold the dry ingredients into the wet mixture before adding in the mini semi-sweet chocolate chips.

Pour the brownie batter into the prepared baking pan and bake for 12-15 minutes. Check for doneness with a toothpick.

Allow the brownies to cool in the pan for about 30 minutes and then cut out heart shapes with a cookie cutter.

Bloom the unflavored gelatin in cold water. Combine the frozen raspberries and granulated sugar in a saucepan over medium heat until it resembles a puree. Add the gelatin and strain to remove seeds.

Whip the heavy whipping cream with powdered sugar and vanilla extract until stiff peaks form.

Gently fold the cooled raspberry puree into the whipped cream until combined.

Fill heart-shaped molds with raspberry mousse, place brownie hearts on top, and freeze for at least 4 hours.

Unmold the mousse after allowing to sit at room temperature for 15-20 minutes.