Heat oven to 400°F. Lightly grease the cups of a standard muffin pan; or line with paper baking cups, and grease the paper cups.
Whisk together all dry ingredients, including the blueberries.
In a separate bowl, whisk together vanilla, vegetable oil, and buttermilk.
Pour the liquid ingredients into the dry ingredients, stirring just to combine.
Spoon batter into prepared muffin cups to nearly full.
Sprinkle the tops of the muffins with coarse sparkling sugar or cinnamon sugar, if desired.
Bake muffins for 18 to 20 minutes, until a toothpick inserted into the middle of one of the center muffins comes out clean.
Remove the muffins from the oven, and after 5 minutes transfer them to a rack to cool. Serve warm, or at room temperature. Store leftovers loosely wrapped at room temperature.
Yield: 12 muffins.