Lunch Box Frittatas

Preheat the oven to 350 degrees F (175 degrees C). Coat a large 6-cup muffin tin with butter.

Heat oil in a skillet over medium heat. Add tomato, ham, onion powder, and parsley. Cook and stir until tomato is warmed through and juice has evaporated, about 5 minutes.

Whisk eggs, Cheddar cheese, and milk together in a large bowl with salt and pepper.

Divide the ham mixture among the 6 muffin cups. Cover with egg mixture until about 3/4 full. Place muffin tin in a larger baking pan filled with hot water.

Bake in the preheated oven until set, about 25 minutes. Cover with aluminum foil if tops start browning too much.