Preheat oven to 425 degrees F and position the rack in the lower third of the oven.
Generously butter a 12-cup popover tin; set aside.
In a medium bowl, whisk together the milk and eggs. Add the flour, salt and powdered sugar and whisk briefly to incorporate the dry ingredients. There may still be small lumps throughout the batter, which is fine; do not overmix.
Fill each cup of the popover tin with 5 tablespoons of the batter. Bake until the popovers are very puffed and rise above the top of the tin by 3 inches, about 30 minutes. Immediately turn the popovers out of the pan and serve warm.