Preheat your oven to 350 degrees Fahrenheit.
Bring 2 quarts of water to a rapid boil. Add the penne pasta to the boiling water and stir gently. Return to a rapid boil and cook, uncovered, for 8 minutes. (You want to undercook it a couple minutes since you bake it as well.) Drain the pasta and set aside.
While the pasta boils, add the pasta sauce and red peppers to a food processor and puree until smooth.
Rinse the food processor (or use a single serving blender cup) to puree with cashews and broth together until smooth.
In a skillet, add the olive oil and garlic. Cook for 1 minute until garlic is fragrant. Stir in the pureed cashews, nutritional yeast, and salt.
Combine the pasta, cashew cream, tomato sauce, and spinach leaves together in a large bowl (or the same pot used to cook the pasta) and transfer to an 8"x8" baking dish.
In a small bowl, mix the breadcrumbs, Italian seasoning, and black pepper. Sprinkle evenly over the pasta and bake for 25-30 minutes or until breadcrumbs have started to brown and sauce is bubbling.