Makes 9 large popovers

Position rack on lowest rung of oven and preheat to 425°F. Butter nine 3/4-cup glass custard cups. Place them on a jelly-roll pan, leaving space between each cup. Pour all the ingredients into a blender and whirl until smooth. Strain batter if lumpy. Pour 1/3 cup of batter into each cup. Bake, without opening the oven door, for 25 minutes, until the popovers are puffed, nicely browned, and crisp on the exterior. Turn temperature down to 350°F and bake another 15 minutes. Serve immediately.