1. Adjust oven rack to the middle position and heat oven to 200 degrees. Spray a wire rack set in a rimmed baking sheet with vegetable oil spray; place in oven. Whisk flour, sugar, baking powder, baking soda, and salt together in medium bowl. In second medium bowl, whisk together buttermilk, greek yogurt, eggs, and melted butter. Make a well in the center of dry ingredients and pour wet ingredient; gently stir until just combined (batter should remain lumpy, with few streaks of flour). Do not overmix. Let the batter sit for 10 minutes before cooking.