Yes, they are. Yorkshire pudding and crepe-style pancake recipes are made from the same ingredients - eggs, milk, and flour. The ratios can vary only slightly depending on a particular recipe. For example, James Martin's 3-egg recipe vs Delia's pancake recipe ratio per egg: James Martin's Yorkshire pudding: 1 egg / 66.66g flour / 100ml milk  Delia's pancakes: 1 egg/ 55g flour / 100 ml milk