Preheat the oven to 375°F. Cook the pasta according to the package instructions until just under al dente. Drain, return to the pot, and set aside.

Heat the olive oil in a large skillet over medium-high heat. Add the vegan ground beef, breaking it up with a spatula. Once browned, stir in the onion and cook for about 5 minutes until softened. Add the garlic and Italian seasoning, cooking for an additional minute.

Pour in the diced tomatoes and spaghetti sauce. Stir to combine, then let the sauce simmer for about 5 minutes to meld the flavors.

Add the sauce to the pot with the cooked spaghetti, tossing until all the noodles are evenly coated.

Transfer the spaghetti mixture to a 9×13-inch casserole dish. Sprinkle vegan mozzarella and Parmesan over the top. Bake for 30 minutes and serve hot.