1 egg white
2 cups whole milk
6 tbsp. unsalted butter, melted and warm to the touch
1 3/4 cups flour
1 tsp. salt
6 tsp. clarified butter
In large mixing bowl, beat eggs and egg white on medium speed until pale and frothy (about 3 min.). Meanwhile, heat milk in the microwave or in a saucepan on low heat until just warm to the touch. Add milk to the eggs; beat until combined (about 30 sec.). Add 6 tbsp. butter, beating until combined (about 30 sec.); reduce speed to low and add flour and salt, mixing just until the batter is the consistency of heavy cream and lightly bubbled (about 30 sec.). Let rest at room temperature (30 min.), covered. Place 1/2 tsp. clarified butter in each popover tin. Loosely cover pan with foil, placing pan on a baking sheet. Heat in a preheated 425° oven for at least 15 min. Pour batter into a container with a spout. Remove hot pan from oven; discard foil. Carefully pour batter into the prepared cups, filling just less than 2/3 full. Return popover pan on the baking sheet to the oven; bake without opening the oven door 25 min.; reduce heat to 325° and continue baking until popovers are golden brown (14-18 min.). Remove from oven and let popovers rest 1 min. before gently lifting popovers from the pans. Serve immediately.
Good to Know: To clarify butter, cut unsalted butter into small pieces; melt in a saucepan over low heat, simmering undisturbed, not allowing the butter to sizzle until the fats separate (10-15 min.). Strain the mixture, discarding the white milk solids and retaining the clear yellow clarified butter. Refrigerate in a tightly sealed glass container up to one month.