Preheat oven to 375ºF and adjust rack to middle position. Place muffin liners inside each muffin cup (I like to use this brand). Whisk oat flour, arrowroot, sorghum flour, rice flour, gelatin, baking powder, baking soda and salt in a medium bowl and then set aside.
Cream butter, coconut oil, and whole cane sugar for 1 minute on medium-high speed in the bowl of a standing mixer. Add eggs, one at a time, beating well after each addition. Add the vanilla extract. On medium-low speed, beat half of dry ingredients in two batches, alternating with the buttermilk until just combined. Remove bowl from mixer and gently fold in the berries. Using a 2-inch cookie scoop, spoon muffin batter into muffin cups. Bake 25 minutes or until golden. Cool for 5 minutes before serving.