In a bowl with a spout, combine eggs, milk, flour, salt and dry mustard and blend with a hand mixer until well combined. Place in refrigerator for at least 30 minutes.
Preheat oven to 425º. Place 1 teaspoon oil in each hole of a 12 hole muffin tray. Place on top rack in the oven and bake until the oil is hot and almost smoking.
Remove pan and immediately pour equal portions of batter into the muffin tins. It should be hot enough that it sizzles. Quickly return to the oven and bake for 15-20 minutes, until they have risen and are golden brown. Do not open the oven while baking.
Serve immediately. They will fall a little once removed from the oven creating a hole in the center for butter or gravy.