Clean all your vegetables. Using a speed peeler (we are using a great one from Status Metlika) peel the carrots and celery stalk into thin strips. Add them to a large pot. Halve the unpeeled onion and crush unpeeled cloves of garlic. Add to the pot. Also add mushrooms, cauliflower, and leek. Tie the herbs together using a string and add them to the pot.
Season the vegetables with peppercorns, tomato paste and vegetable oil. Place over high heat and sauté the vegetables for about 3 - 4 minutes. Add water and bring to a boil, then reduce the heat to low and cook for 45 - 60 minutes. If you like you can add salt once the stock almost cooked.
strain and use
Strain and discard the vegetables. Set a large sieve over a big bowl or pot. Pour the stock through. Use immediately or store in a fridge or freezer, once cooled completely.