Heat oil in pan. Once hot, add ½ cup of chopped onions, ½ cup of finely chopped carrots, ½ teaspoon of finely chopped garlic and 1 tablespoon of finely chopped celery. Sauté for 4-5 mins.
Next, add 3 to 3 ½ cups of sliced or chopped button mushrooms. Sauté the mushrooms with the veggies until all water evaporates from the pan. Mushroom will release plenty of water when sautéing.
Next, add 3 to 3 ¼ cups of finely chopped tomatoes. Mix and sauté for 3-4 minutes.
Add 2 tablespoons of tomato paste, ¼ cup of chopped fresh basil, ½ teaspoon of dried oregano, salt as needed, 1 teaspoon of red chili flakes (can omit), ¼ teaspoon of black or white pepper
Add ½ cup of red wine and ½ cup of water or vegetable stock. Use a good quality wine as this will greatly influence the flavor of the dish. You can use water instead of wine.
Mix well and cover with a lid. Simmer for 30 minutes until sauce has thickened. Check the pot or pan every few minutes, stir, and add a bit more water ¼ cup at a time if the sauce is cooking down too quickly and sticks to the pan
Once the bolognese sauce is done and thickened, turn off the heat and set it aside. Bring 5 cups of water with 1 teaspoon salt to a boil in a medium to large pot or pan. Place the spaghetti in the hot boiling water.
Reserve ½ cup of the pasta water and set aside. Then strain the cooked spaghetti in a colander. Do not rinse.
Add the noodles to the sauce. Use tongs or a pasta scoop to toss and thoroughly coat the spaghetti. If the sauce looks too thick you can add some of the reserved pasta water, and continue to gently mix. Enjoy!