Blueberry Flax Muffins

Name: Blueberry Flax Muffins
Prep time: 15 min
Cook time: 25 min
Total time: 40 min
Cuisine: American
Ingredients: 2 cups (240g) King Arthur Unbleached All-Purpose Flour; 1/4 cup (25g) flax meal; 1/4 cup (35g) flax seeds, optional; 1 1/2 teaspoons baking powder; 1/2 teaspoon baking soda; 1/2 teaspoon table salt; 4 tablespoons (57g) unsalted butter, room temperature; 1/2 cup (106g) light brown sugar; 2 large eggs; 2 teaspoons King Arthur Pure Vanilla Extract; 3/4 cup (170g) buttermilk or plain yogurt, or 2/3 cup (152g) liquid whey; 1 1/2 cups (213g) blueberries, fresh or frozen; coarse sparkling sugar, to sprinkle on top, optional