Non-fat cooking spray
2 large eggs, lightly beaten, at room temperature
1 cup milk, at room temperature
1 cup all-purpose flour
1/2 teaspoon salt
Preheat the oven to 400° F for 20 minutes. Coat each cup of a six-cup muffin or cupcake tin with non-fat cooking spray.
In a smaller bowl, lightly whisk the eggs until they change color. Whisk in the milk.
In a medium bowl, whisk together the flour and salt until well blended. Gently whisk the egg mixture into the flour mixture until only small lumps are left, and set aside.
Place the muffin tin in the oven for 4 minutes. At 3 minutes, give the batter a light whisk. Using an oven mitt, remove the hot tin from the oven and immediately divide the batter among the prepared cups. Bake for 25 minutes without opening the oven door. The popovers will be puffy, with crisp brown crusts and hollow, moist interiors. Serve immediately, with butter if desired.