Preheat your oven to 350°F (175°C). Grease an 8×8-inch baking pan with butter or cooking spray and line it with parchment paper.

In a medium saucepan, melt the chopped semisweet chocolate and unsalted butter over low heat until smooth and creamy.

Remove from heat and stir in granulated sugar and light brown sugar until combined. Add eggs one at a time, whisking well after each addition. Stir in vanilla extract.

In a separate bowl, sift together flour, cocoa powder, and salt. Gradually fold this mixture into the wet ingredients until no dry streaks remain.

Pour the brownie batter into the prepared baking pan and smooth the top. Bake for 20–25 minutes, or until a toothpick inserted comes out with a few moist crumbs.

Allow the brownies to cool completely in the pan before transferring to a cutting board and slicing into petit fours.

Heat heavy whipping cream in a saucepan until simmering. Pour over chopped semisweet chocolate and let sit for 2–3 minutes, then stir until smooth.