1. Core the capsicums and chop into 4 large pieces each; place in a very hot oven directly under the grill until the skin blackens completely. Remove and wrap in aluminium foil immediately when done and set aside for about 15 minutes.
2. Quarter the onions and tomatoes and place in a baking pan along with the unpeeded garlic and bake for around 30 minutes in a hot oven - until the skins start to brown slightly.
3. In the meanwhile peel the blackened skin off the capsicums, it should come off very easily.
4. Peel the garlic, toss into a blender along with the onions, tomatoes, canned tomatoes, peeled capsicums, stock and blend to a consistency you like - I like mine reasonably smooth.
5. Freeze it, stick it in the fridge, or leave it on the stove and heat it when ready to eat: garnish with fresh torn basil leaves and season with salt and pepper.
It also works as a simple lazy pasta sauce.