Preheat your oven to 350°F (175°C) and line an 8"x8" metal baking pan with parchment paper.

In a microwave-safe bowl, combine the unsalted butter and 1 ½ ounces of semi-sweet chocolate. Heat in the microwave until melted and glossy.

Add the granulated sugar and light brown sugar to the melted chocolate mixture, whisking until shiny.

Mix in vanilla extract and large eggs, whisking until the batter is smooth.

Gently fold in the flour, cocoa powder, espresso powder (if using), and fine sea salt until just combined.

Pour the batter into the prepared pan and spread evenly.

Bake for 30-35 minutes or until the top is shiny and a toothpick comes out with moist crumbs.

Let cool completely on a wire rack, about 30-45 minutes.

For the ganache, heat heavy cream in a small saucepan until simmering, then pour it over chopped chocolate and let sit for 2 minutes.

Whisk the chocolate and cream together until smooth and let cool to room temperature.

Once the brownies are cool, cut them into 16 bites. Whisk the ganache until light and fluffy.

Pipe the whipped ganache onto each brownie bite.