Rich dark chocolate cake brownies, made from scratch, are studded with chocolate chips and topped with homemade marshmallows. They're a decadent treat!
Preheat the oven to 350 °F. Spray an 8- x 8-inch baking pan with baking spray and line with parchment paper. Set aside.
Make the brownie batter: In a small mixing bowl, sift together the flour and cocoa powder to remove any lumps. Add the espresso powder (if using), salt, and baking powder, and whisk until combined.
Combine the dark chocolate and butter in a medium microwave-safe bowl and melt on High heat in 30 second bursts, stirring until smooth after each interval, about 1½ to 2 minutes. Allow the mixture to cool for 5 minutes.
Whisk in the granulated and brown sugar, then the eggs (one at a time), and finally the vanilla.
Stir in the flour mixture just until combined. Don't over-mix so you don't create too much gluten (that will toughen the brownies). Fold in the chocolate chips (if using).
Add the topping: Pour the batter into the prepared baking pan, and smooth the top with a small offset spatula. Top with the marshmallows in a grid pattern (4 x 4), pressing them in gently.
Bake the brownies for 35 to 38 minutes or until a cake tester or toothpick inserted in the center comes out clean (or maybe with just a few crumbs attached). It might be hard to tell if the center of the brownies are set because of the melting marshmallows. I'd err on the side of caution and go for the longer baking time, if necessary. Once done, remove the brownies from the oven and cool completely in the pan on a wire rack.
Once the brownies are completely cool, carefully lift the parchment to remove the brownie slab from the pan and place it on a cutting board. Cut the slab into 2-inch squares (around each marshmallow) with a sharp knife, wiping off the knife between cuts.
Serve with a large glass of milk (or your favorite non-dairy alternative) and enjoy!
Storage instructions: Brownies are best when eaten within 1 to 2 days of baking. Store the cut brownies in an airtight container at room temperature. For longer storage, freeze cut or uncut brownies, wrapped in plastic wrap and stored in an airtight plastic bag, for up to 3 months.
Notes
The dark chocolate and dark chocolate cocoa power used here give these brownies a deep rich chocolate flavor. You can use semisweet or milk chocolate and regular unsweetened cocoa powder if you prefer. Also, adding espresso powder to the brownie batter helps deepen the chocolate flavor. It’s optional, but highly recommended.Making homemade marshmallows is easier than you think, and you can flavor them as you like. Here we're using marshmallows flavored with Irish Whiskey, and you can use another spirit, fruit juice, or whatever flavoring liquid that you prefer. If you're using store bought marshmallows, cut them in half before placing them on the brownie batter.For slightly thinner brownies, use a 9- x 9-inch inch baking pan. Reduce the baking time by about 5 minutes (but start checking at the 30 minutes mark).