Preheat the oven to 375 degrees and make sure your oven rack is in the bottom third of the oven with several inches of space between it and the rack above.
Place the ungreased popover pan in the oven to heat.
In a small saucepan slowly heat the milk to just warm but not hot (about 125 degrees). Remove from the heat.
In a bowl, beat the eggs, salt, and pepper and slowly add the milk. Mix well.
Slowly add the flour and mix until just combined. Some lumps are okay.
Remove the hot popover pan from the oven and spray generously with cooking spray.
Pour in the batter, filling the cups 3/4 full.
Drop two cubes of cheese into the batter.
Bake 40 minutes and DO NOT OPEN THE OVEN DOOR. They could collapse of you do.
Serve warm, or room temperature. Also freezes well.