Step 1: Preheat oven to 350 degrees.
Step 2: Thinly slice onions; set aside. Slice mushrooms; set aside. Slice scallions; set aside.
Step 3: In a large skillet, heat 2 teaspoons of olive oil. Add sliced onions, and saute until fragrant (about 3 minutes).
Step 4: Add sliced mushrooms, and saute until cooked through (about 7 - 10 minutes).
Step 5: Turn off the flame and add baby spinach leaves to the hot skillet. Mix well. Allow mixture to cool down.
Step 6: In a bowl, whisk eggs, crumbled goat cheese, grated parmesan, and salt & pepper together.
Step 7: Lightly grease a 6-cup muffin pan.
Step 8: With a spoon, scoop out mushroom-spinach mixture, and evenly distribute between cups.
Step 9: Pour egg and cheese mixture over the mushrooms. Sprinkle tops with sliced scallions.
Step 10: Bake for 25 minutes, or until tops are golden brown.
Karen Biton-Cohen blogs at K. abc Food & Photography.