Preheat oven to 325 degrees. Insert paper liners into 36 mini muffin cups.

In the bowl of an electric mixer fitted with a paddle attachment, cream the butter and sugar on medium speed until light and fluffy, about 3 minutes. Turn mixer to low and add the eggs, one at a time, mixing until each egg is fully mixed in, scraping down the sides of the bowl with each addition. Add the vanilla and mint extracts and mix well.

In a separate large mixing bowl, whisk together the sweet rice flour blend, baking powder, baking soda, and salt. With the mixer on low, add the flour mixture and buttermilk to the creamed butter starting with 1/3 of the flour mixture, then half the buttermilk, half the remaining flour mixture, the rest of the buttermilk mixture and the rest of the flour mixture. Mix until just combined. Remove bowl from mixer and scrape the sides and bottom of the bowl well with a large spatula. Add the food coloring a couple of drops at a time until you get the color the shade of mint chip ice cream. Fold in the chopped chocolate.

Fill the prepared muffin cups 2/3 full. Bake for 12 – 17 minutes or until the tops are springy to the touch and a toothpick inserted in the center comes out clean. Allow to cool in pan for 5 minutes then remove to a wire rack to cool completely before frosting.

In a heatproof bowl of a stand mixer, combine the egg whites, sugar and salt. Place over a pan containing an inch or two of simmering water (the bottom of the mixing bowl should not touch the hot water). Whisk, either by hand or with a handheld mixer, constantly until the mixture feels warm to the touch and the sugar is melted. Rub a bit between your forefinger and thumb to feel if it is smooth. This will take about 2 minutes.

Attach the bowl to the mixer fitted with a whisk attachment and beat until the mixture is glossy, fluffy and completely cool, about 10 minutes. With the mixer on medium-low speed, add the butter a few tablespoons at a time mixing well after each addition. Once the butter has been fully incorporated, add the vanilla, mix well, add the cooled melted chocolate and mix well. With a spatula, scrape the sides and bottom of the bowl and stir it for a minute or two to knock out the air bubbles. Your frosting should be completely smooth. If the frosting starts to curdle or separate after adding the butter, don’t worry. Just keep beating it until it is smooth again. Frost cooled cupcakes.