Remove sausage from casing and saute until cooked through. Set aside.

Remove stems from 3/4 portobello mushrooms and remove scales. Clean the outer part of the mushroom with a damp paper towel.

Saute zucchini in olive oil for 3-4 minutes (or until softened), add tomatoes and pinch of salt. Add the chopped basil and loosely cover and let saute for an additional 3-4 minutes. Add the sausage and combine all the ingredients and continue to cook an additional 4-5 minutes.

Place bread crumbs and cheese in a bowl. Add the hot mixture to the bowl and combine with spoon (or hands). Fill the mushroom caps with mixture and place in a lightly greased baking dish.

Bake at 400/425 F covered with foil 15-20 minutes. Uncovered 10 minutes. Sprinkle with grated fontina cheese at the end.