Preheat the oven to 425°F. Place 1 tsp oil in each of 6 large or 12 small muffin pan cups, or 2 Tbsp oil in an 8 or 9 inch baking pan or 12-inch oven-proof frying pan (check the handle). Preheat the pan and the oil for at least 10 minutes before adding batter.
In a large measuring cup, whisk the eggs.
Add all the other ingredients, whisking until smooth. Batter can be made ahead; stir before pouring.
Working quickly, add batter to the hot pan, distributing equally.
Bake until golden brown, puffed and firm, about 20 minutes for 12 muffin-sized, 30 minutes or more for 6 “Texas Muffins”, 35 minutes for a baking dish or frying pan.