The pancakes can be cooked on an electric griddle. Set the griddle temperature to 350 degrees and cook as directed. The test kitchen prefers a lower-protein all-purpose flour like Gold Medal or Pillsbury. If you use an all-purpose flour with a higher protein content, like King Arthur, you will need to add an extra tablespoon or two of buttermilk.
1. Adjust oven rack to middle position and heat oven to 200 degrees. Spray wire rack set inside rimmed baking sheet with vegetable oil spray; place in oven.
2. Whisk flour, sugar, baking powder, baking soda, and salt together in medium bowl. In second medium bowl, whisk buttermilk, sour cream, eggs, and melted butter together. Make well in center of dry ingredients and pour in wet ingredients; gently stir until just combined (batter should remain lumpy with few streaks of flour). Do not overmix. Let batter sit 10 minutes before cooking.
3. Heat 1 teaspoon oil in 12-inch nonstick skillet over medium heat until shimmering. Using paper towels, carefully wipe out oil, leaving thin film on bottom and sides of pan.
4. Using 1/4-cup dry measuring cup, portion batter into pan in 4 places. Cook until edges are set, first side is golden brown, and bubbles on surface are just beginning to break, 2 to 3 minutes. Using thin, wide spatula, flip pancakes and continue to cook until second side is golden brown, 1 to 2 minutes longer. Serve pancakes immediately, or transfer to wire rack in preheated oven. Repeat with remaining batter, using remaining oil as necessary.
