In a medium bowl, whisk together the gluten-free flour, almond flour, salt and baking soda.
In the bowl of a stand mixer fitted with a paddle attachment, or using a hand mixer, cream together the butter, coconut oil, brown sugar and granulated sugar on medium-high speed until light and fluffy, about 2-3 minutes.
Add the eggs and vanilla and mix until well-combined. Scrape down the sides and bottom of the bowl.
With the mixer running on low, slowly add the dry ingredients to the wet ingredients and mix until well-combined. Scrape down the sides and bottom of the bowl, then mix again until fully incorporated. Stir in the old-fashioned rolled oats, Cadbury Mini Snowballs and mini chocolate chips.
Cover the bowl and refrigerate for at least 1 hour, or up to 3 days.
Preheat the oven to 350°F. Line large baking sheets with parchment paper or silicone baking mats.
Scoop the cookie dough into round balls, 2 tablespoons per ball. Place on the prepared baking sheet, about 2 inches apart.
Bake for 11-13 minutes, until the edges are golden brown but the centers are still soft.
Remove from the oven and cool on the baking sheets for 5 minutes. Transfer to a wire rack to cool completely.