These brownies are like a simple version of my favorite dessert ever, triple chocolate mousse cake. A rich brownie layer is topped with a light and fluffy Nutella espresso mousse, making for one seriously decadent dessert. To take it completely over the top, I covered the whole thing in homemade chocolate curls. Because it’s Valentine’s Day, and I’ll take any excuse to add more chocolate to an already chocolaty dessert. Case in point – this recipe originally called for an espresso mousse, but I couldn’t resist incorporating this Nutella mousse I made last Valentine’s Day. This indulgent dessert is sure to please whoever you’re making it for, but I won’t judge you if you decide to keep it all to yourself.
Heat oven to 350º. Butter the bottom of 8-inch square baking dish and line with parchment or foil, leaving several inches overhang on two sides. Butter the bottom and sides of the parchment or foil and set pan aside.
Melt the butter in a large bowl. Whisk in the espresso powder until it dissolves completely, then whisk in the sugar. Add the eggs, one at a time, whisking well after each addition. Stir in the vanilla. Whisk in the dry ingredients until just incorporated.
Pour the batter into the prepared pan and bake for about 30 minutes, until a toothpick inserted in the center comes out with a few moist crumbs attached. Allow to cool completely before topping with the mousse.
To make the mousse, combine the espresso and hot water in a small bowl. Whisk in Nutella and Kahlua if using. Using a hand mixer or a stand mixer fitted with the whisk attachment, beat heavy cream until it just forms stiff peaks. Using a rubber spatula, gently fold in the Nutella mixture. Scrape the mousse onto the top of the cooled brownies and spread evenly with an offset spatula. Refrigerate for at least an hour or up to overnight.
Using the parchment/foil handles, lift the brownies from the pan. Cut into squares and top as desired. Serve immediately.
Heavily adapted from Bakingdom