Blueberry Swirl Muffins

Preheat oven to 400°F. Prepare a standard 12-cup muffin pan with nonstick cooking spray or liners.In a medium bowl, whisk together flour, baking powder, baking soda and salt; set aside.In a large bowl, melt butter. Whisk in the sugar, brown sugar and vanilla. Then whisk in the eggs, one at a time, until well combined. Alternate adding flour mixture and milk, beginning and ending with flour, until batter is smooth.Using a cookie scoop or large spoon, fill each prepared muffin cup a little less than halfway with batter. Add a heaping teaspoon of blueberry preserves and gently swirl into the batter of each muffin with the end of a chopstick or skewer. Divide remaining batter evenly among muffin cups. Add another heaping teaspoon of blueberry preserves to the top of the batter in each muffin cup and gently swirl again with the end of a chopstick or skewer. Sprinkle the top of each muffin generously with sparkling sugar.Bake until muffin tops are golden, 20-22 minutes. Cool muffins in muffin pan for 5 minutes, then transfer to wire rack and cool 5 minutes before serving warm