Wash mushrooms and carefully remove the stem. Leave the ribs in tact.
Prepare a baking sheet – spray or drizzle with olive oil.
Arrange mushrooms on the baking sheet, tops (round side) facing down, and lightly spray or drizzle with oil.
Sprinkle salt, pepper, and Italian seasoning onto mushrooms. Spoon sauce into each mushroom and spread evenly – using about 2 Tablespoons each.
Add cheese – about 1/4 cup per mushroom – and desired toppings.
Broil on low for 10 minutes.