Line a standard muffin pan with paper baking cups.
In a medium bowl, whisk together the gluten-free flour, almond flour, baking powder, baking soda, salt and nutmeg.
In the bowl of a stand mixer, or using a hand mixer, beat together the eggs and sugar until very light and fluffy, about 2-3 minutes.
With the mixer running on low, slowly drizzle in the oil. (Do this slowly so you keep the eggs and sugar fluffy.) Add the lemon juice, vanilla and mix.
With the mixer running on low, add ⅓ of the dry ingredients followed by ½ of the yogurt. Mix until combined then add another ⅓ of the dry ingredients. Add the rest of the yogurt and mix until combined. Then add the rest of the dry ingredients and mix until incorporated. Scrape down the sides and bottom of the mixer and mix for another 15-20 seconds until the batter is very smooth.
Stir in the blueberries with a rubber spatula. Using a kitchen scoop or large spoon, portion the batter evenly into the prepared muffin pan. Sprinkle the raw sugar evenly over the top of the muffins, if using.
Refrigerate the muffins for 20 minutes before baking (or overnight). Preheat the oven to 425°F.
Bake the muffins for 10 minutes at 425°F. Then reduce the oven temperature to 375°F and continue to bake for 10-15 minutes, until the tops are lightly browned and a toothpick inserted into the center comes out clean.
Let the muffins cool in the pan for 5 minutes, then transfer to a wire rack to cool completely.