Mix the buttermilk, vegetable oil, and vanilla extract in a bowl; stir in the sugar. Whisk in the flour, baking powder, baking soda, and salt, combining the batter with just a few strokes to moisten. Leave the lumps.
In a separate bowl, whisk the egg and lemon juice together; gently stir into the batter. Refrigerate the batter for at least 30 minutes, up to 1 hour.
Heat a large skillet over medium heat and grease with the butter. Pour 1/3 cup of batter per pancake into the skillet and cook until bubbles appear on the surface, about 2 minutes. Flip with spatula and brown the other side, about 2 more minutes.