Preheat oven to 450°F.

Spray the cups of the popover pan with nonstick cooking spray. Pour 1/2 tsp melted butter into each cup.

Wisk together the eggs, milk, and remaining butter. Add in salt then flour. Wisk until smooth.

Divide the batter between the cups. Bake for 20 minutes.

Reduce the temperature to 325°F and bake for an additional 15 minutes.

Remove from cups and let cool before serving.