Place the roughly chopped onion, carrot and celery into the Thermomix bowl. Chop on Speed 6, 5 seconds.
Add the minced garlic and olive oil and saute for 3 minutes, 100 degrees, Speed 2. Scrape down the sides of the bowl and repeat for a further 3 minutes, 100 degrees, Speed 2.
Add the chicken stock powder, sugar, water tinned tomatoes and fresh tomatoes and cook for 25 minutes, 100 degrees, Speed 1 (see notes).
Allow to cool and then mix until smooth by very slowly increasing to Speed 6 (see notes).
Season with salt and pepper and serve immediately with fresh basil.