1.Heat oven to 350 degrees Fahrenheit. Place mini cupcake liners in 2 mini muffin/cupcake pans. Set aside.
2. To make the brownie layer: In a pan over low heat add the chocolate chips and butter. Stir continuously until melted Remove from the heat and add the brown sugar, eggs, cocoa powder salt and vanilla. Stir well to combine.
3. Spoon the brownie batter in to each well about 3/4 full. Bake until the brownies are dry on top and almost firm to the touch, about 12 minutes. Remove from the oven and allow to cool.
4. While the brownies cool, make the buttercream frosting. Combine the butter and confectioners sugar in the bowl of your stand mixer. Mix on low speed at first, then increase the speed until combined. Add in your heavy cream, vanilla extract, peppermint extract, and mix on medium to high speed for 8 minutes until light and creamy. If not using immediately, store in a container in the refrigerator until ready to use, mix again until light and fluffy. Using a pastry bag and tip, pipe the frosting onto each cupcake. Top with miniature chocolate chips if you so choose!