In a small bowl, mix the blueberries, granulated sweetener, and water. Use a fork to gently "bruise" the blueberries, making sure not to mash them up. Place the berries in the refrigerator to macerate for at least 2 hours and up to 24 hours.
Preheat the oven to 350°F. Grease a muffin tin or silicone muffin cups.
In a large bowl, combine the almond flour, baking powder, soda, and powdered sweetener. Whisk to combine.
Take the blueberries out of the fridge and drain the liquid. Pat them dry with a paper towel. Take 1 to 2 tablespoons of the dry muffin mix and add it to the berries. Toss to coat and set aside.
Add the vanilla, sour cream, and eggs to the remaining muffin mixture. Whisk until fully combined.
Fold in the blueberries.
Divide the batter between 10 muffin cups.
Bake for 20 minutes. Let the muffins cool for 5 minutes before removing them from pan.