Cook the Spaghetti: Boil water in a large pot, add salt, and cook spaghetti according to package instructions until al dente. Reserve 1 cup of pasta water before draining.

Prepare the Bolognese Sauce: Heat olive oil in a large skillet or saucepan over medium heat. Add onion, carrot, and celery, and sauté until softened (about 5–7 minutes). Add minced garlic and cook for 1 minute until fragrant. Stir in the chopped mushrooms and cook for 5–7 minutes, allowing them to release their moisture and become golden.

Build the Sauce: Add tomato paste and stir for 1–2 minutes to enhance the flavor. Pour in the red wine (if using) and cook until it reduces slightly. Add the crushed tomatoes, vegetable broth, lentils (if using), oregano, basil, smoked paprika, and chili flakes. Stir to combine.

Simmer: Cover and let the sauce simmer for 20–25 minutes, stirring occasionally. If the sauce thickens too much, add a splash of reserved pasta water. Stir in soy sauce or tamari, and adjust salt and pepper to taste.

Combine: Toss the drained spaghetti with the mushroom Bolognese sauce. Add a bit of reserved pasta water. This helps to coat the noodles evenly.

Serve: Plate the spaghetti and garnish with fresh basil and nutritional yeast or vegan Parmesan.