Preheat the oven to 350 degrees.
Make zucchini noodles by using a julienne slicer (or a spiralizer if you prefer). Set aside in a large bowl.
To make your sauce, start by heating the oil in a large stock pot or Dutch oven.
Cook the onion and garlic until soft, about 5 minutes.
Add the chopped mushroom and allow to cook another 10 minutes.
Stir in the tomatoes, tomato sauce, oregano, marjoram, salt, and pepper. Allow to simmer for 15 minutes. Stir in the fresh basil.
While your mushrooms are cooking during the sauce-making, start making your bean balls. Put your beans into a large bowl and mash (I use a potato masher for this). It's okay to have a few beans in tact.
Add the rest of the ingredients and stir well. Use your hand to knead the mixture together, making sure the ingredients are well incorporated.
Roll the bean mixture into 1½ inch balls and place them on a baking sheet that is either lightly coated with oil or lined with parchment paper. You will get about 28-30 balls.
Bake in the preheated oven for 16-18 minutes, turning once halfway through the cooking time.
To serve, place a serving of zucchini noodles on a plate, top with 4-6 meatballs, and finally cover it all with the tomato sauce. If you aren't vegan and can enjoy dairy, feel free to top it with some freshly grated parmesan cheese. Enjoy!