Preheat your oven to 450°F. Thoroughly spray a 12-cup muffin tin with cooking spray.
In a medium bowl, whisk together the eggs and milk until well combined.
Add in the flour and salt, and whisk until smooth with no lumps.
Stir in the melted butter until the mixture is well combined.
Pour the batter into the muffin tin, filling each cup about 2/3 to 3/4 full. You might end up with 11-12 popovers.
Place the muffin tin in the oven and bake for 20 minutes at 450°F. Ensure there’s enough room in the oven for the popovers to rise as they can get quite tall!
Reduce the heat to 350°F and bake for an additional 10-15 minutes. Check after 10 minutes to ensure they’re not getting too dark. The popovers should be puffed and deep golden brown.
Serve immediately with eggs or jam.