Preheat your oven to 350°F (177°C). Line a muffin tin with 10-12 silicone or parchment paper liners. For slightly larger muffins, opt for 10 cups; for smaller, lean portions, use all 12.

In a large mixing bowl, combine the almond flour, sweetener, baking powder, and sea salt. Stir well to evenly distribute the dry ingredients.

Add the melted butter (or coconut oil), almond milk, eggs, and vanilla extract to the bowl. Whisk until you have a smooth, lump-free batter.

Gently fold in the fresh or frozen blueberries, being careful not to crush them so the batter doesn't turn blue.

Divide the batter evenly among the prepared muffin liners, filling each about 3/4 full.

Bake for 20-25 minutes, or until the tops are golden brown and a toothpick inserted in the center comes out clean. Allow the muffins to cool in the pan for 5 minutes before transferring to a wire rack to cool completely.