Preheat oven to 350°F. Rinse portobello caps and dip in a mixture of egg and milk, beaten together. (About one egg and 1/8 cup of milk for every four caps.) Dip in seasoned breadcrumbs. Put the caps on a greased, oven-safe dish or baking pan.
Top with chunky homemade tomato sauce and a generous handful of shredded mozzarella, and bake for about 15 minutes or until the cheese is melted and golden brown. Serve with spaghetti (topped with more sauce) and pinot noir.