Spinach and Artichoke Stuffed Portabello Mushrooms

Source: recipe by Rachael Ray, Food Network
adapted by http://theresalwaysthyme.blogspot.com/

8 portabello mushroom caps
olive oil, for brushing mushrooms, plus 1/4 cup
1 (10-ounce) box frozen chopped spinach, defrosted
1 can quartered artichoke hearts, drained well
1 1/2 cups ricotta cheese
1 egg yolk
1 clove garlic, grated
salt and freshly ground black pepper
freshly grated nutmeg, about 1/8 teaspoon
1/2 cup Parmigiano-Reggiano
Preheat grill to medium-high or the oven to 425 degrees F.

Using a damp towel, brush mushroom caps to clean. Using a brush, coat the caps with olive oil and grill with lid down or roast in the oven about 5 to 6 minutes, turning once, until tender but still firm at center.

Squeeze the water out of the spinach using a kitchen towel. Mix spinach with the artichokes, ricotta cheese, egg yolk, grated garlic, salt and pepper, to taste, and nutmeg. Add some shredded mozzarella to the mix if you like.

Remove mushroom caps from grill.

Spoon some filling into mushroom. Sprinkle the caps with Parmigiano and cook at least 10 -15 minutes more in the preheated oven to until the top is browned and the filling is cooked through.