Preheat the oven to 450°F(230°C). Generously grease 2 nonstick mini muffin pans. In a large bowl, stir together the flour, ½teaspoon salt, ¼teaspoon pepper, and the chives. In another bowl, whisk together the milk, eggs, and butter. Pour the wet ingredients over the dry ingredients and whisk until just combined (don’t worry if some lumps remain).
Bake the popovers
Fill the prepared muffin cups with batter to within about ¼inch (6mm) of the rims. Place a scant teaspoon grated cheese in the center of each filled cup. Bake, without opening the oven door, for 10 minutes. Reduce the oven temperature to 350°F(180°C) and bake until the popovers are brown and fully puffed, 8–10 minutes longer. Transfer to a platter and serve warm.