Preheat oven to 425 degrees and spray a rimmed baking sheet with cooking spray. Slice the mushrooms and dice the onion.

Heat 1 tablespoon olive oil in a large skillet over medium heat. Saute mushrooms and onion over medium heat for about seven minutes or until mushrooms are browned, stirring occasionally.

Meanwhile, slice the mozzarella and chop garlic (if not using pre-minced).

Stir the spinach and garlic into the skillet with the sauteed mushrooms, then continue to stir and cook over medium heat until spinach is dark green and wilted.

Strain the excess liquid out of the spinach and mushrooms, pressing down with a wooden spoon to help this process. Stir the cooked veggies together in a large bowl with the ricotta, oregano, sea salt, and crushed red pepper.

Sprinkle a large cutting board and rolling pin with flour and roll out your pizza dough. Cut dough into four equal pieces.

Add some cheesy ricotta filling to half of each section of dough, then top that with mozzarella and Parmesan.

Stretch and fold the dough over the filling, and crimp the edges to make four calzones (see Notes, below). Place calzones on the prepared baking sheet, then brush each with olive oil.

Bake at 425 degrees for 16-18 minutes, or until calzones are a beautiful golden brown.

Serve your spinach mushroom calzones with marinara sauce, for dipping. (I prefer Simply Nature organic marinara from ALDI, but use your own fave.)