George Chiala Farms - George's Recipe of the Month.

Ingredients

• 1 tablespoon unsalted butter, at room temperature, for greasing the baking dish
• All-purpose flour, for dusting
• 3 tablespoons extra-virgin olive oil
• 12 ounces cremini mushrooms, cleaned and quartered
• 1 medium onion, chopped
• 1 teaspoon kosher salt
• 1/2 teaspoon freshly ground black pepper
• 2 cups heavy cream, at room temperature
• 1 3/4 cups whole milk, at room temperature
• 1/3 cup all-purpose flour
• 2 cups grated Pecorino Romano
• 2 cups shredded mozzarella
• Two 5-ounce bags baby spinach, coarsely chopped
• 1/4 packed cup chopped fresh basil
• 2 cloves garlic, minced