In a large mixing bowl, combine the eggs, oil, sugar, vanilla, and buttermilk.
Heat griddle according to manufacturer's instructions.
Once griddle is hot and you are ready to cook, whisk the Bisquick into the wet ingredients.
Grease the griddle with butter. Spoon or ladle a scant ¼ cup per pancake onto the griddle.
Once pancake batter puffs and starts to bubble, flip.
Once cooked through, transfer pancakes off the griddle to a serving sheet or hotel pan.
Regrease the griddle with butter and repeat in batches, working through the batter.