Heat oven to 400 degrees.

Line a small sheet pan with parchment or use a cast iron skillet (without parchment).

Place cleaned Portobellos in pan.

Drizzle tablespoon of olive oil over both caps.

Add Salt and Pepper to taste.

Roast the Portobellos for 10 minutes.

While the Portobellos are roasting, sauté the baby spinach with a little bit of olive oil cooking spray or olive oil in a medium skillet.

Remove caps from oven.

Divide spinach between caps.

Add 1/4 cup of spaghetti sauce to each cap.

Add 1/4 cup of shredded mozzarella to each cap.

Bake for 5 - 8 mjnutes until cheese is melted and bubbly.

Flip to broil for 2 - 3 minutes until cheese is lightly browned.

Garnish with basil and parmesan, if desired.

Enjoy!