Melt the butter in a saucepan or microwave, and allow it to cool slightly so it doesn’t cook the egg when added.
Mix in the sugar with the melted butter until fully combined. Add the eggs and mix well.
Add the wet ingredients: Pour in the warm espresso (or espresso powder), vanilla extract, and peppermint extract. Stir to combine.
Fold in the dry ingredients: Sift together the flour, cocoa powder, and sea salt, then gently fold them into the wet mixture until well incorporated.
Prepare the baking pan: Line a baking dish with parchment paper (cut it to fit the bottom), and grease the pan with cooking spray, olive oil, or butter.
Pour and spread the batter evenly into the prepared baking dish.
Bake for 30-35 minutes. The top should be crisp, and the brownies will feel slightly firm to the touch. They will continue to set into a fudgy texture as they cool.
Cool completely before slicing or frosting to maintain the perfect fudgy consistency.
Peppermint Buttercream
Prep the butter: Add softened butter to an electric mixer. If you’re mixing by hand, slightly melt the butter to make it easier to work with.
Whip the butter: Mix the butter until it’s smooth and creamy.
Add the powdered sugar: Gradually mix in powdered sugar, along with the peppermint extract and vanilla extract.Adjust the consistency: Add about 3 tablespoons of milk to achieve your desired texture. If the frosting is too runny, add more powdered sugar. If it’s too thick, add a bit more milk.
Taste test: Taste the frosting and adjust the flavor to your liking. If you want a stronger peppermint flavor, add a little more peppermint extract, or if you prefer more vanilla, add extra vanilla extract.Pipe the frosting: Once the brownies have completely cooled, pipe the buttercream on top.
Notes
The brownies I made were extra large! make them mini by cutting them into 18-20 slices rather than 12.