01 - Preheat oven to 350°F. Grease a 24-cup mini muffin tin or line with mini paper liners.
02 - Melt butter and chopped chocolate in a heatproof bowl over simmering water, stirring until smooth. Remove from heat and cool slightly.
03 - Whisk sugar, eggs, vanilla extract, and peppermint extract into chocolate mixture until well combined.
04 - Sift flour, cocoa powder, and salt into bowl. Fold gently until just combined; avoid overmixing.
05 - Spoon batter evenly into prepared mini muffin cups, filling each about 3/4 full.
06 - Bake for 12-15 minutes until tops are set and toothpick inserted in center comes out with moist crumbs.
07 - Let cool in tin for 5 minutes, then transfer to wire rack to cool completely.
08 - Place chopped chocolate in small bowl. Heat cream until steaming, pour over chocolate, let sit 1 minute. Add peppermint extract and stir until smooth and glossy.
09 - Spoon or pipe ganache onto each cooled brownie bite. Garnish with mint leaves or chocolate shavings if desired. Let ganache set before serving.