Heat your oven to 170 degrees F, sometimes called the "keep warm" setting.Get out 3 bowls: large, medium, and small.Add the butter to the large bowl and microwave until it is melted. Set aside to cool a little bit.In the medium bowl, whisk together flour, sugar, salt, baking soda, and baking powder.Add the buttermilk and milk to the melted butter.Separate the eggs: add the whites to the small bowl and the yolks to the wet ingredients in the large bowl. Whisk in the yolks.Use a small whisk of fork to beat the egg whites a little bit, just 20 seconds or so until they start getting a little bubbly. It will help them fold in evenly.Add the buttermilk mixture to the dry ingredients and stir roughly with a wooden spoon. Don't overdo it! Just barely combine it. There should still be streaks for flour. See photos.Beat the egg whites a little then add them to the batter. Fold in gently. It's okay if there are still streaks of egg white.Heat a griddle or large frying pan over medium heat.When it is hot, smear a little bacon grease over the griddle.Scoop the batter using a half cup measurement.When bubbles on top start to pop, flip the pancakes. They should be a nice golden brown.Continue cooking for another 2-3 minutes until they are golden on both sides.Remove the pancakes to a cooking rack and keep warm in the oven that you turned on.Repeat with the remaining batter.Serve with lots of butter and syrup. And peanut butter. What, am I the only one??