Finely chop the fresh mint. Place chopped mint + sugar into the bowl of a stand mixer and, using your fingertips, rub mint into the sugar until the sugar becomes aromatic and somewhat moist. (It won't get nearly as moist as it would with lemon zest, but it should take on some of the mint's moisture.) Set the sugar mixture aside to marinate as you prepare the rest of the ingredients.
Position a rack in the lower third of oven and preheat to 325°F. Generously grease and flour a 6-well bundtlette pan. Tap out excess flour.
In a medium size mixing bowl, whisk together the flour, baking powder and salt; set aside.
Add the butter to sugar mixture and, using the paddle attachment, beat together on medium speed until creamy and smooth (about 3-5 minutes). Gradually add the beaten eggs, beating for about 1 minute after each addition, and scraping down the sides of the bowl as needed. Reduce the speed to low and add the flour mixture in three additions, blending each addition until just incorporated. (Do not over mix.)
Spoon batter into the prepared pan; try to spread out the tops as evenly as possible. [Note: I used a soup spoon to drop the batter into the wells. I found it was easier to dollop 2 spoonfuls on opposite sides, and then gently coax them together with the spoon.]
Bake for 17-20 minutes, or until a toothpick inserted into the middle of a cake comes out clean.
When cakes are ready to come out of the oven, transfer the pan to a cooling rack and let the them rest upright in the pan for 15 minutes, then gently tap the pan on a work surface to loosen the cakes. Set the rack over a sheet of waxed paper and carefully invert the cakes onto the rack.
While the cakes are still a bit warm, dip a pastry brush into the bourbon and give each cake a healthy slather. [If you want, you can brush the entire cake, not just the bottom.] Set cakes aside on a sheet of wax paper as you prepare the glaze.
In a medium size mixing bowl, combine confectioners' sugar and bourbon. Mix until smooth. If it's too thin, add more sugar, if it's too thick, add a little bit more bourbon...not too much, as a little bit of liquid goes a long way. Once you've reach your desired consistency and boozyness, drizzle/drench each cake. Allow the glaze to harden for about 10 minutes.