Preheat the oven to 325 degrees F. Spray a mini muffin pan generously with baking spray.
Melt the unsweetened chocolate in a bowl in the microwave. Remove from the microwave and stir in 8 mints until all melted. Let cool slightly.
In the bowl of a stand mixer with the paddle attachment, cream 1 stick of the butter with the sugar. Beat in the eggs one at a time. With the mixer on low, slowly drizzle in the cooled chocolate mixture, mixing until combined. Add the flour and mix thoroughly. Scrape the sides of the bowl with a rubber spatula, add the mint extract and mix again.
Using a tablespoon or cookie scoop, scoop the batter into the prepared mini muffin pan. Bake until done, 11 to 13 minutes. Turn upside down out of the pan and allow to cool.
Combine 25 to 30 mints in a bowl with the remaining 1 tablespoon butter and the bittersweet chocolate. Microwave and stir until melted and smooth.
Dip the brownie bites in the chocolate, concentrating on the top "cone" part. Allow to set for a few minutes. Chop the remaining mints and sprinkle them on the top. Set in the freezer for 10 minutes if you need them to set right away. Yum!