1. Preheat the oven to 400 F and spray a 9 x 13″ pan with nonstick spray. Fill a large pot with water over high heat on the stove. Once it reaches a boiling temperature, generously salt the water and add the pasta. Cook until just al dente, usually about 6-7 minutes. Drain, and set the pasta aside to cool.
2. Heat a large non-stick skillet on the stove to medium-high and add the olive oil. After a minute, add the diced onion and sauté for 4-5 minutes until softened. Add the minced garlic and cook for another minute, before adding in the pepper, zucchini and carrots. Cook on low-medium heat for about 5-6 minutes or until the carrots are softened. Add in the peas, oregano, salt and pepper and cook for another minute or so. Remove the skillet from heat.
3. Add the drained pasta to the cooked vegetables, along with the pasta sauce. Stir everything together until thoroughly combined, then empty the contents into the prepared casserole dish. Top the casserole with the mozzarella cheese, followed by the parmesan cheese.
4. Bake the pasta for 15-20 minutes in the oven, until the cheese is browned and bubbly. Remove the casserole dish from the oven and allow it to cool for 5 minutes before serving.

Leftovers can be stored in an airtight container, in the fridge, for 3-4 days.