Step 1

Set oven to broil, with the baking rack positioned at the lowest level in the oven.

Step 2

Gently rinse and dry each mushroom. Remove the stem from the cap. Chop the stems only and place into a small bowl, reserve.

Step 3

Heat a large sauté pan over medium heat. Add 1 tablespoon of olive oil and heat until hot but not smoking.

Step 4

Add minced garlic and onion to the pan. Sauté for about 3 minutes, until onions are tender and translucent, stirring constantly.

Step 5

Add chopped mushroom stems, saute until tender, 1 to 2 minutes.

Step 6

Add sausage, break into small pieces as it cooks, 4 minutes.

Step 7

Add the chopped spinach to the pan, stir and cook for 1 minute.

Step 8

Add the bread crumbs, stir and cook for 2 minutes.

Step 9

Turn off heat. Add the chopped parsley, basil, grated parmesan cheese, mozzarella cheese, and stir to combine. Season with salt and pepper. Set aside.

Step 10

Lightly coat each mushroom cap with olive oil, and season each side with salt and pepper.

Step 11

Stuff each mushroom with about 2 tablespoons of filling, pressing the stuffing into each mushroom cap.

Step 12

In an ovenproof pan or foil-lined sheet tray, add a thin layer of olive oil to coat the bottom of the pan/tray. Evenly spread out rosemary and thyme on top of the olive oil.

Step 13

Place each stuffed mushroom on top of the bed of herbs. Sprinkle each mushroom with bread crumbs.

Step 14

Broil in the oven for 10 minutes, or until mushrooms are tender, and the breadcrumbs on top are golden brown.