Prepare the zucchini noodles: Use a spiralizer to create noodles from the zucchini. Set aside.

Cook the mushrooms: Heat olive oil in a large skillet over medium heat. Add the chopped portabella mushrooms and sauté until tender and browned, about 5 minutes. Remove and set aside.

Sauté aromatics: In the same skillet, add more olive oil if needed. Sauté onions and garlic until fragrant and softened, about 3 minutes.

Make the sauce: Stir in crushed tomatoes, oregano, basil, and red pepper flakes. Let it simmer on low heat for 10 minutes, stirring occasionally. If the sauce is too thick, add vegetable broth.

Combine: Return the mushrooms to the skillet and mix them into the sauce. Cook for another 5 minutes to allow flavors to meld. Season with salt and pepper.

Prepare zucchini noodles: Lightly sauté zucchini noodles in a separate pan for 2 minutes or microwave them for 1 minute to warm. Avoid overcooking.

Assemble and serve: Divide zucchini noodles into bowls, top with the mushroom Bolognese, and garnish with fresh basil and vegan Parmesan if desired.