INGREDIENTS
Nonstick cooking spray
4
6-inch portobello mushroom caps
4 cups
spinach, chopped
1 cup
breadcrumbs (preferably panko)
1 cup
shredded mozzarella cheese
2
shallots (1 finely chopped, 1 thinly sliced)
1
large tomato, diced
3 tbsp
grated pecorino romano cheese, plus shaved pecorino for topping
3 tbsp
extra-virgin olive oil, plus more for drizzling
Kosher salt and freshly ground pepper
1/2 cup
ricotta cheese
4
stalks celery, peeled and thinly sliced