Preheat your oven to 350°F /180°C. Grease an 8.5 x 4.5-inch loaf pan with butter or line it with parchment paper.
In a bowl add the eggs, sweetener, vanilla extract. Using a mixer, mix for 2-3 minutes or until the eggs look frothy.
Add the heavy whipping cream and mix again.
Combine the dry ingredients in a different bowl: the almond flour, baking powder, and coconut flour.
Combine the wet and the dry ingredients using the mixer. Add the butter and continue mixing.
Fold in the blueberries and then transfer the batter to a loaf pan.
Bake for about 45-50 minutes at 350F or until cooked through (it should pass the toothpick test).
Let it cool down and enjoy.
For the best results, when baking with almond flour use the super fine one. Different brands have different textures.You know it's baked when you poke it with a toothpick and comes out almost clean with a moist crumb or two but with zero uncooked batter