Preheat oven to 450 degrees.
Divide butter between popover cups. Brush 1 tablespoon of the melted butter along the bottom and up the sides of the cups.
Place the popover pan in the oven while assembling the ingredients.
In a large mixing bowl whisk together the eggs and milkuntil no streaks of yellow remain, approximately 1 minute. Add the flour, remaining butter, chili powder, salt, and pepper to the bowl. Stir until only small lumps remain. Don’t overmix.
Stir in the cheddar and scallions.
Remove the popover pan from the oven.
Using a ladle, divide mixture between the hot popover cups.
Place the pan back in the oven and bake for 20 minutes.
Reduce heat to 350 degrees.
Bake for an additional 15-20 minutes, or until golden brown. (Note, after the 15 minute mark you’re safe to open the oven door to check on them.)
Once the popovers are done, cut a small slit in the top with a sharp paring knife to let steam escape. (This won’t deflate the popovers, in fact it will keep them crispy!)