Note that the batter has to rest for an hour before baking. It’s not absolutely essential, but it makes a big difference in volume and texture.
When I make a roast I save and render the fat and freeze in ice cube trays for making Yorkshire pudding the next time, since my roast recipe doesn’t make much in the way of drippings.
3 large eggs , at room temperature
1 1/2 cups whole milk , at room temperature
1 1/2 cups unbleached all-purpose flour (7 1/2 ounces)
3/4 teaspoon table salt
3 tablespoons beef fat
1. Whisk eggs and milk in large bowl until well combined, about 20 seconds. Whisk flour and salt in medium bowl and add to egg mixture; whisk quickly until flour is just incorporated and mixture is smooth, about 30 seconds. Cover batter with plastic wrap and let stand at room temperature for at least 1 hour or up to 3 hours.
2. After removing roast from oven, whisk 1 tablespoon of beef fat into batter until bubbly and smooth, about 30 seconds. Transfer batter to 1-quart liquid measuring cup or other pitcher.
3. Measure 1/2 teaspoon of remaining 2 tablespoons beef fat into each cup of standard muffin pan. When roast is out of oven, increase temperature to 450 degrees and place pan in oven to heat for 3 minutes (fat will smoke). Working quickly, remove pan from oven, close oven door, and divide batter evenly among 12 muffin cups, filling each about 2/3 full. Immediately return pan to oven. Bake, without opening oven door, for 20 minutes; reduce oven temperature to 350 degrees and bake until deep golden brown, about 10 minutes longer. Remove pan from oven and pierce each pudding with skewer to release steam and prevent collapse. Using hands or dinner knife, lift each pudding out of tin and serve immediately.