Preheat oven for 350ËšF. Prepare baking sheets with silpat mat or parchment paper (two if you have them).
Whisk together the rice flours, xanthan gum, baking soda, and salt. Set aside.
Melt the butter, 60% chocolate, semisweet chocolate chips, and unsweetened chocolate in a microwave safe bowl. Or if you have a double boiler use that. Microwaving chocolate can be tricky, the key is short intervals. I do it in 15-20 second intervals (the closer to completely melted, the shorter the time). It took about 6 times or so. Stir in between every go in the microwave. The chocolate should be smooth without any noticeable chunks. Allow to cool slightly, but still fluid.
While you're melting the chocolate, beat together the eggs, sugar, and vanilla. Beat on high until light and frothy, about 5 minutes. This step is what will make the cookies have that shiny, crackly exterior.
Turn the mixer to low, and add the melted chocolate/butter mixture to the eggs.
Add the flour mixture. Scrape down sides of the bowl to make sure everything is evenly incorporated.
Mixture should be silky and shiny. Slightly thick but with fluidity.
Mix in the white chocolate chips and the chopped Andes mints.
Drop the cookies onto a baking sheet about 2 inches apart.
If you only have one baking sheet, prescoop the rest of the dough as well. Due to the chocolate content, this dough will harden up pretty quickly. It's perfectly fine to bake once they've hardened, but they're more difficult to scoop.
Bake for 10 minutes, turning half way. Bake until the top looks glossy and cracked.
Cool on the baking sheet at least 5 minutes. Transfer parchment or mat onto a cooling rack and cool until you can easily peal the cookies off the mat. Cool on cooling rack for another 20-30 minutes until completely cooled. You want to allow the cookies to set.
These cookies are great when cooled, you can also warm them. They stay great for a few days in an airtight container.