Ingredients:

1 stick (8 tablespoons) unsalted butter, at room temperature

2/3 cup sugar

1 teaspoon  pure vanilla extract

1 extra-large egg, at room temperature

½ cup sour cream (low-fat is fine, non-fat won’t work)

2 medium-size ripe bananas, 1 mashed and 1 diced)

1 ½ cups all-purpose gluten free flour

¾ teaspoon xanthan gum

1 ½ teaspoons baking powder

¼ teaspoon  baking soda

¾ frozen (or fresh) blueberries

Directions:

Preheat the oven to 350 degrees. Grease or line a standard 12-cup muffin tin with unsalted butter and set aside.

In a large bowl, cream the butter and the sugar until light and fluffy. Add the vanilla and the egg and mix until well combined. Next. Add in the sour cream, and then the mashed banana, and mix again until well blended.

Add the flour, xanthan gum, baking powder, baking soda, and salt to the wet ingredients., reserving a few tablespoons of flour in a separate bowl. Beat the batter well until it becomes thicker and a bit more elastic, which means that the xanthan gum has been activated.

Carefully fold the diced bananas into the batter. Toss the blueberries in the reserved flour, and carefully fold them into the batter as well. Divide the batter evenly among the twelve prepared muffin cups.

Place the muffin tin into the center of the preheated oven and bake at 350 degrees for 20 to 25 minutes, or until the muffins are brown around the edges and a toothpick inserted into the center of the middle muffin comes out with a few moist crumbs attached.