Heat oil in a large ovenproof non-stick skillet over medium-high heat. Sprinkle ground beef with half of the salt and pepper and cook for 8 minutes, breaking into small chunks with back of spoon, until meat is browned and completely cooked. Drain and set aside on a plate until ready to use.

In a medium sized bowl, whisk together eggs, milk, onion powder and remaining salt and pepper.

Return beef to the non-stick skillet and stir in onions and spinach. Cook until spinach wilts, about 1 minute. Stir in tomatoes. Turn heat to low and pour in egg mixture. As eggs set around edge of skillet, using spatula, gently lift cooked portions to allow uncooked egg to flow underneath. Cook until bottom is set and top is almost set, about 5 minutes.

Sprinkle cheese over top and place skillet under preheated broiler for 2 minutes to melt cheese and puff up frittata, or cover with lid and cook for a couple minutes on stovetop. Loosen around edge of frittata. Cut into wedges and serve with ketchup for dipping.

Cooking Tip

If you have Big Batch Beef in the freezer, use 2-1/2 cups of that instead of fresh ground beef to make this recipe super speedy.