Preheat oven to 350 degrees. Lightly grease or line an 8 cup muffin pan.
In a large mixer bowl whisk coconut flour, salt, brown Swerve, xanthan gum, and baking powder until fully combined and there are no lumps in the Swerve or the flour. If needed use fingers to press out the lumps of brown Swerve
Add eggs. Beat on low 10 seconds to moisten the dry ingredients. Increase speed to medium and beta on medium about 30 seconds or until everything is fully combined
Scrape down the sides of the bowl. Add the butter and vanilla extract. Beat on medium another 30 seconds or until fully combined
Again scrape down the sides of the bowl. Add the sour cream. Beat on medium about 20-30 seconds or until fully combined
Scrape down the sides of the bowl once again. GENTLY fold in the blueberries. Be very careful not to smash the blueberries.
Scoop the batter out about 1/4 cup at a time into each prepared muffin cup. Use a butter knife and smooth out the top of each muffin for a more even cook
Bake at 350 degrees for 25-30 minutes or until lightly golden and a tester comes out clean. They will be soft but will firm up as they cool
Once they are baked allow to cool in the pan for about 15 minutes or until they are firm enough to handle
Transfer to a wire rack and allow to cool completely before serving. Store at room temperature in an airtight container for up to 3 days