1 cup milk
1 cup flour
1 teaspoon sugar
3/4 teaspoon salt
1/4 cup (1/2 stick) unsalted butter
We always called them German pancakes too -- I think this is where "Dutch" (Deutsche) came from.
My batter is similiar:
2/3 C milk
2/3 C flour
It scales marvelously.
The key to good rising is to make sure the pan is adequately buttered. If the batter sticks to the walls, it won't rise well. Also, beat a lot of air into the batter.
I've used large muffin tins for individual servings. They come out similiar to a pop-over, but a little denser (eggier).
We like them with creamy Irish butter and homemade jam.