Speculoos Brownie Cake

Ingredients

• Nonstick cooking spray
• 1/2 cup unsalted butter
• 31/2 ounces bittersweet chocolate, chopped
• 11/3 cups lightly packed light brown sugar
• 1 teaspoon pure vanilla extract
• 1/2 teaspoon instant espresso powder
• 3 large eggs, at room temperature
• 1/2 cup all-purpose flour
• 1 teaspoon baking powder
• 1/2 teaspoon salt
• 3/4 cup speculoos cookie butter
• 6 tablespoons unsalted butter, at room temperature
• 2/3 cup confectioners' sugar
• 1/4 teaspoon salt
• 2 tablespoons heavy whipping cream
• Chocolate shavings, for garnish

Directions

1. Set yourself up: heat the oven to 350 degrees F (180 degrees C), then mist a 9-inch/23 cm springform pan lightly with nonstick cooking spray. For the brownie batter, melt the butter in a medium saucepan set over medium heat. Take the pan off the burner, stir in the bittersweet chocolate after it has rested for about 30 seconds, and whisk until the mixture is sleek and smooth.
2. Whisk in the brown sugar, vanilla, and espresso powder until the batter looks even. Add the eggs, 1 at a time, whisking after each one. Scatter the flour, baking powder, and salt over the top, then switch to a sturdy spatula and fold until you no longer see any flour.
3. Scrape the brownie batter into the prepared springform pan and smooth it out. Bake for 20 to 25 minutes, until the cake rises a little and the surface looks glossy with only the slightest cracks.
4. Move the pan to a wire rack and let the cake cool all the way before you release the springform sides. While it cools, make the speculoos frosting.
5. In a large bowl, beat the speculoos and butter with an electric mixer on medium speed for 1 minute, until lighter and fluffier. Add the confectioners' sugar, salt, and cream, then beat for 1 minute more, until the frosting is airy and easy to spread.
6. Spread the frosting over the cooled cake, finish with chocolate shavings, and slice into wedges for serving.