Sift the flour, sugar, baking powder, baking soda and salt into a large mixing bowl. In a separate large bowl, lightly whisk the eggs. Add the milk, sour cream, half the melted butter and the vanilla, whisking to blend. Make a well in the dry ingredients and pour the egg mixture into it. Whisk the ingredients together just until blended. Fold the blueberries and lemon zest into the batter.
Heat a large skillet or griddle over medium heat and coat with some of the remaining melted butter. For each pancake, pour about 1/4 cup of the batter into the hot skillet. Cook 3 or 4 pancakes at a time, depending on the size of the skillet. If the batter seems too thick, thin it with 1 to 2 tablespoons milk. When bubbles begin to form and "pop" on the pancake's surface, after about 1 minute, and the outer edge looks done, flip it over and cook briefly for about 30 seconds on the other side.
Recipe adapted from Home Cooking with Trisha Yearwood (c) Clarkson Potter 2010