https://www.food.com/recipe/gordon-ramsays-yorkshire-pudding-424498

In a blender, combine the eggs, milk, flour, and salt. Blend until well combined and place in the refrigerator until ready to use (allow to rest for at least 30 minutes).

Preheat oven to 425°F.

Put 1 teaspoon of the oil (or beef drippings) into each section of a 12-hole Yorkshire pudding tray or muffin tray and put into the oven on the top shelf until very hot, almost smoking.

As soon as you take the tray from the oven, pour in the batter to three-quarters fill the tins (it should sizzle) and immediately put back into the oven.

Bake until the Yorkshire puddings are well risen, golden brown and crisp, 15 to 20 minutes. Don't open the oven door until the end or they might collapse.

FOR GLUTEN FREE
https://glutenfreecuppatea.co.uk/2017/10/01/gluten-free-yorkshire-pudding-recipe-dairy-free-low-fodmap/
this makes 14... so decrease
200 g cornflour (cornstarch)
6 eggs
300 ml milk (dairy-free if necessary)
50 ml cooking oil