Preheat the oven to 350ºF (177ºC). Spray the wells of a 24 or 12 count mini-cupcake pan with nonstick spray. Set aside.
In a medium saucepan over medium heat, melt the butter and chopped chocolate, stirring frequently until completely smooth. Allow to cool for about 15 minutes.
Whisk sugar into cooled chocolate mixture until combined. Add the eggs one at a time, whisking after each addition until smooth. Whisk in the vanilla. Add the flour and salt and stir gently until completely combined.
Spoon the batter into the wells of the mini-cupcake pan. Bake brownies for 12-13 minutes or until a toothpick inserted in the center comes out mostly clean. Allow brownies to cool completely in the pan before removing and decorating.
I used leftover vanilla buttercream2 for my football stripes, but this quick royal icing will also do the trick. Use a small zip top bag with the corner snipped off or an icing bag fitted with a Wilton #3 tip. Allow icing to set before serving. Store brownies covered at room temperature up to 1 week or in the freezer up to 2 months.
Notes
Room temperature eggs: these incorporate into batter much more easily than cold eggs, although this is not absolutely necessary.
For buttercream laces: you'll want to decrease the original recipe significantly. Use ¼ cup (57g Tablespoons) butter, 1 cup (120g) of powdered sugar, ¼ teaspoon vanilla extract, and about 1 to 1 and ½ Tablespoons (22mL) milk or cream. Salt to taste if needed. You'll have the best luck whisking everything together in a small bowl or using a handheld mixer. You will have some leftover.
All nutritional values are approximate and provided to the reader as a courtesy. Changing ingredients and/or quantities will alter the estimated nutritional calculations.