My recipe is from the Purity Cookbook I got from the same grandmother-in-law who taught me how to make Palt. It was first published in 1967 and reprinted through the years.
The recipe is called Popovers as I make them in muffin tins. For Yorkshire Pudding, you use a cake pan. As usual, I double the recipe because we love leftovers but the ingredient list below is for a single recipe.
1 c flour
1/4 tsp salt
1 c milk
1 Tbsp melted butter or marg
Preheat oven to 450F. Pour 1/2 tsp vegetable oil or melted shortening in each of 8 muffin cups, cast iron popover pans or Pyrex custard cups. (hint - I get 12 popovers instead of 8 because I don't want them to spill over into the oven while baking, plus it really messes up the muffin tins if you cook them empty.) Place pans in oven to heat while making the batter. (Hint - be ready for smoke as the hot oil does smoke a fair bit.)
Blend together flour and salt. Gradually add milk and beat until smooth.
Beat eggs until thick and light.
Add eggs to flour mixture with melted butter. Beat for 2 minutes.
Pour batter into pans quickly and carefully as pans are very hot and you don't want them to cool down. (Hint - worry more about filling the pans quickly rather than neatly)
Bake at 450F for 20 minutes, then reduce heat to 350F and bake another 20 minutes.
(HINT - I never cook mine that long probably because I make my popovers smaller. I cooked them for 15 minutes at 450F and then 5 minutes at 350F. )
The popovers are soft, airy and chewy in the centre.
For Yorkshire Pudding, the recipe suggests using 1 1/2 Tbsp roast beef drippings or vegetable oil in an 8" Pyrex cake dish. Heat pan and follow above recipe. Bake 20 minutes at 450F and then 20 minutes at 350F. Cut into squares and serve. Makes 9 squares.