Preheat oven to 450F and lightly grease a 12-count popover pan or 12 count muffin tin with cooking spray. Set aside.
Place eggs in a large bowl and, using an electric mixer, beat on low speed until frothy.
With mixer on low, add milk and melted butter and beat until well-combined.
Sprinkle salt over batter and stir.
Add flour, stirring on low-speed until batter is completely combined.
Evenly divide batter into prepared muffin tin and transfer to 450F oven*.
Bake on 450F for 20 minutes, then, without opening the oven door, reduce the heat to 325F and bake an additional 15 minutes.
Remove from oven and serve immediately -- these taste great topped with butter!
*Important Note! Place a cookie sheet lined with parchment paper or foil beneath your popover pan or muffin tin. The butter tends to spill over the sides as the batter bakes and will drip onto your oven, causing a lot of smoke and a messy oven. Avoid this and set yourself up for easy cleanup by placing a pan underneath.