Stuffed Portobello

I was going to make this for one of Blake's vegetarian friends, without the beef, but he didn't end up eating with us so I made it closer to this recipe, which I saw on foodgawker. We both really liked how this turned out.

Ingredients:
2 Large Portabello Mushrooms
1 Tbsp Olive Oil
Sea Salt to taste
Freshly Ground Black Pepper
1 lb Ground Beef
frozen sliced carrots
2 cloves Garlic, finely chopped
1/2 Yellow Onion, finely chopped
italian seasoning
1 Tbsp Olive Oil
Spinach
Marinara sauce
Monterey Jack Cheese, grated

Directions:

Scrub the mushrooms and scrape out the gills. Season with salt, pepper and olive oil and cook in a 350 degree oven for about 10 minutes. Meanwhile, cook the onion in the olive oil over medium heat. Add the ground beef and brown, and then add the carrots. When thawed, add some marinara sauce, just to moisten the mixture. Remove mushrooms from oven and fill with stuffing. Top with cheese and bake until melted and browned.