Spray 2 mini muffin tins (each with 24 cups) with nonstick spray. Whisk the eggs, milk, pepper, and salt in a large bowl to blend well. Stir in the ham, cheese, and parsley. Fill prepared muffin cups about 2/3rds of the way with the egg mixture. Bake until the egg mixture puffs and is just set in the center, about 4 to 5 minutes. Using a rubber spatula, loosen the frittatas from the muffin cups and slide the frittatas onto a platter. Serve immediately.