Preheat oven to 400°F.  Line a baking sheet with foil and drizzle with olive oil

Slice each squash in half lengthwise.  Scoop out seeds, sprinkle with salt and pepper, place skin side up on the prepared baking sheet.  Bake 30-35 minutes or until tender.

Saute Italian sausage over medium heat until browned and cooked through.  Drain fat and set aside.  Wipe out the pan and saute spinach until wilted.  Season spinach with salt and pepper.

In a medium sized bowl, stir together ricotta cheese, 1/4 cup pepperoni, cooked Italian sausage, 1/2 of the diced green pepper, 1/4 cup mozzarella, and spinach.  

Carefully flip squashes so they are skin side down.  Spread 1-2 spoonfuls of pizza sauce in the opening, then place ~1/4 cup of ricotta mixture in the wells.  Add another layer of pizza sauce, then top with remaining mozzarella cheese and any desired toppings.

To freeze, let pizzas cool to room temperature for ~1 hour, then wrap completely in foil and place in the fridge overnight.  Place foil wrapped pizzas in a gallon size ziplock bag and freeze.

Thaw pizzas overnight in the fridge.  Bake at 400°F ~20 minutes wrapped in foil, then ~20 minutes uncovered or until cheese is hot and bubbly.  Top with other pizza toppings like fresh basil, pepper flakes, or parmesan cheese.