Place eggs, milk, flour blend and salt in a large container fitted with a lid. Whisk ingredients with a fork until well combined. Then cover container with the lid and shake vigorously 1 minute.
Place batter in the refrigerator at least 30 minutes and up to 3 days.
Preheat oven to 425°F.
Put 1 teaspoon oil (or beef drippings) into each cup of a 12-cup muffin pan. Place pan into preheated oven on the top shelf until it’s very hot, almost smoking, about 8 to 10 minutes.
Remove pan from oven and, working quickly, pour batter into cups, filling each ¾ full. The pan should sizzle. Immediately put pan back in the oven and bake until puddings rise and turn golden brown and crisp, 18 to 20 minutes. (Don’t open the oven door until the end or they might collapse.)
Turn puddings onto a wire rack to cool slightly. Serve warm or cool.
Yorkshire Pudding batter can be made 2 or 3 days ahead and refrigerated; it’s ready to bake after resting 30 minutes. Store baked puddings in a plastic bag at room temperature 1 to 2 days; reheat 5 minutes in a 350F oven.