Boil The mushrooms and the Cauliflower. I boil them in a pressure cooker until tender. (Use just enough water to cover the ingredients.)

After they are boiled, strain them and reserve the cooking liquid.

In a Blender, combine mushrooms, cauliflower and tomato puree using the reserved cooking liquid to turn it into a smooth puree with no vegetable bits.

Sautee the bell peppers with olive oil or butter whatever's available until they are soft.

Boil the pasta in 3 litres salted boiling water for 9-10mins until the pasta is cooked (timings differ from pasta to pasta)

Strain the pasta

Add the pasta to the sauteed vegetables. Saute it for 4-5mins. Then add the sauce and cook for another 2-3 minutes after mixing thoroughly.

Top up with grated cheese if wished.

Alternatives:-
1.Make a white sauce with the mushroom and cauliflower by substituting tomato puree with cheese.
2.You can omit the mushrooms from the sauce and saute them with the bell peppers or on their own.
3.Grated carrots can be also be sauteed So also grated red cabbage.
4.Sliced olives either black or green can be added and mixed just before serving. (I prefer green with red sauce and black with white)
5.If preferred saute a few cloves of garlic before adding the vegetables. It really improves the flavour.
6.Meat can be added too for a more heavier alternative. Preferably chicken.