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 almost to the top with the egg mixture. Bake until the egg mixture puffs and is just set in the center, about 8 to 10 minutes. Using a rubber spatula, loosen the frittatas from the muffin cups and slide the frittatas onto a platter. Serve immediately.