Instructions

• Preheat the oven to 350°F (180°C). Lightly coat a 9-inch (23 cm) springform pan with nonstick cooking spray.
• In a medium saucepan set over medium heat, melt ½ cup (113.5 g) unsalted butter. Remove the pan from the heat, add 3½ ounces (99.22 g) finely chopped dark chocolate, let sit for about 30 seconds, then whisk until smooth and glossy.
• Whisk in 1⅓ cups (293.33 g) lightly packed light brown sugar, 1 teaspoon vanilla extract, and ½ teaspoon instant espresso powder until fully combined and smooth.
• Whisk in the 3 room-temperature eggs, one at a time, scraping the sides of the pan as needed so each egg is fully incorporated before adding the next.
• Sprinkle in ½ cup (62.5 g) all-purpose flour, 1 teaspoon baking powder, and ½ teaspoon salt. Use a rubber spatula to fold the dry ingredients into the batter until no streaks of flour remain.
• Spread the batter evenly into the prepared springform pan and bake for 20–25 minutes, or until the cake has puffed slightly and the top is shiny and just barely cracked.
• Transfer the pan to a wire rack and cool completely before removing the sides of the springform pan.
• While the cake cools, make the frosting: in a large bowl, use an electric mixer on medium speed to beat ¾ cup (177.44 g) speculoos cookie butter and 6 tablespoons unsalted butter (at room temperature) for 1 minute, until light and fluffy. Scrape down the bowl as needed.
• Add ⅔ cup (80 g) powdered sugar, ¼ teaspoon salt, and 2 tablespoons heavy whipping cream to the bowl. Beat on medium speed for about 1 minute, or until the frosting is fluffy and spreadable. Scrape the bowl to ensure everything is well combined.
• Spread the frosting over the completely cooled brownie cake, garnish with chocolate shavings, and cut into wedges to serve.
• Store leftovers covered at room temperature for up to 3 days or in the refrigerator for up to 5 days.