Ingredients :

• Whole milk — No semi-skimmed. The fat gives body to the batter and that slightly sweet milky undertone found in the crust. If you only have semi-skimmed, it will work, but the result will be a bit blander.
• All-purpose flour (T55) — Neither too strong nor too weak. Bread flour would make the popovers too elastic and tough. Cake flour would cause them to collapse. The one you have in your cupboard, the classic kind, is exactly what you need.
• Room temperature eggs — Taken from the fridge at the last moment, a cold egg weighs down the batter and slows the rise. Set them on the counter 30 minutes before starting — same logic as for a sponge cake.
• Baking powder — Just a small amount. It’s not there to do all the rising on its own — steam does 90% of the work — but it gives a boost at the very beginning of the bake.