Traditionally, Yorkshire Pudding was cooked in roasting pan in the fat thrown from the roast. But nowadays, our meat is really too lean to do that. So I use olive oil and a little butter for making popovers. And because we love the crispness of the popped part of the pudding, I always make several small puddings.
Pour olive oil into the bottoms of pyrex bowls and add a small amount of butter to each. If there is any fat from the roast add that as well. (We had a little bit of caramelized roast chicken fat on this occasion.) Put the bowls onto a jelly roll pan (this is important). If you don't have pyrex bowls, you can use muffin tins. But it's essential to place the muffin tins onto a jelly roll pan to catch the spitting fat.
While the oven and pyrex bowls are heating up whisk the eggs and salt until the eggs are light and frothy. Then whisk in the milk and finally quickly whisk in the flour.
The oil should be smoking hot.
When the batter is poured in, there is an immediate sizzle and bubbling.
Bake on the top shelf for about 30 minutes til they are dark golden brown and well popped.
Serve immediately. The hollow core is just made for being filled with gravy. (This is an orange gravy from chicken a l'orange.)
We had LOTS of gravy. (This was from a pork braised with many vegetables that were then put through a food mill to produce a rich and delicious gravy.) We also had roasted potatoes and parsnips, steamed green beans and pork that had been braised with fennel, onions, turnip and red pepper. And popovers. Of course. That's why there's LOTS of gravy.