Place a wire rack in the bottom third of the oven. Preheat oven to 450°F.
Make the pimento cheese: In a large bowl, mix together the Cheddar cheese, cream cheese, hot sauce, Worcestershire sauce, cayenne pepper, paprika, jalapeño, onion, garlic, and dill pickles until thoroughly combined. This mixture can be made up to 1 day in advance, but it should be at room temperature when making the popovers.
Make the popovers: Place a 12-well muffin tin in the oven. In a bowl, whisk the eggs until well combined and lightly frothy. Add milk and salt, whisk until the mixture is very well combined and there is a layer of froth on the top, about 30 seconds of vigorous whisking. Add the flour and whisk just until combined; it’s okay if some lumps remain. Let the mixture sit for 2–3 minutes, then whisk one more time.
Remove the muffin tin from the oven and spray with nonstick cooking spray. Fill each muffin well three-quarters full of batter. Top each with a heaping teaspoon of the pimento cheese, and gently press the cheese down into the batter. Bake for 15 minutes, then lower the heat to 350°F and bake an additional 15 minutes, until the popovers are a deep golden brown and well puffed. Do not open the oven during this baking time.
Remove the popovers from the oven and transfer them from the muffin tin to the wire rack. Make a small hole in the bottom of each popover to allow steam to escape. Drop an additional teaspoon of pimento cheese into the top hole of each popover. These are best served immediately.