Adapted from Fine Cooking magazine.
Makes 10 popovers, or 12 in a muffin pan
4 large eggs, at room temperature
1 1/2 cups whole milk or half and half, at room temperature
4 TBSP unsalted butter, melted cooled slightly
1 TBSP Dijon mustard
6oz all purpose flour
3/4 tsp salt
1/8 tsp cayenne
Arrange an oven rack on the middle rung and slide two popover pans onto the rack. Preheat the oven and pans to 450F.
In a blender combine the eggs, milk, melted butter, mustard. Process until blended, about 10sec.
Add flour, salt, cayenne, blend for another 10-15sec.
Set aside the blended mixture while the oven heats.
Once oven and pans are at 450F, moving quickly, remove the pans from the oven, and lightly grease them with the pan spray.
Fill each cup 1/2 to 2/3 of the way full. If using popover pans leave two empty.
Bake without opening the oven for at least the first 20min. Cook 25 minutes.
Pierce each popover with a knife to let the steam escape (as soon as you remove from oven) to help stop them from deflating.