Preheat the oven to 375°F. Lightly spray a muffin pan with nonstick cooking spray and set it aside.
Chop 2 cups chopped baby spinach into small pieces. Slice 1 ½ cups mushrooms.
Heat cooking oil over medium-high heat in a frying pan. Sautee the sliced mushrooms and spinach until spinach wilts, the mushrooms turn brown and shrink in size. This will take about 2-3 minutes. Remove everything from the pan, and add to a plate. Set aside.
Beat four eggs in a large bowl. Add ¼ cup grated parmesan cheese, 2 Tbsp milk, ½ tsp garlic powder, ¼ tsp salt and ¼ tsp ground black pepper.
Divide the mixture into the muffin pan. Bake for 18-20 minutes, or until eggs are cooked. Let cool then use a spatula to scoop onto a rack to cool completely.
Recipe Notes:
Store these egg cups in an airtight container, or tightly wrapped in plastic in the refrigerator for 3-4 days.
To freeze – Wrap each muffin in plastic wrap, then place them in a large freezer bag or container. Remove as much air as possible. These can be frozen for up to 3 months for maximum freshness. Let them thaw in the fridge overnight, or on the counter for about 1 hour.
To reheat – Egg muffins can be reheated for 30-60 seconds in the microwave and ready to eat.