Preheat the oven to 325 F (165 C).

Chop the zucchini into large chunks, about 2 centimetres or 1 inch in diameter, and place it into a large bowl.

Core the peppers and slice them into somewhat fine strips. The peppers take longer than the zucchini in the oven, so chopping them smaller will help even out the cooking time. Add them to the bowl too.

Mince or grate the garlic finely and add it to the bowl.

Add the salt and olive oil to the bowl, and toss very well until everything is coated nicely.

Spread the veggies onto a heavy baking tray or dish. They should just fit in a single layer without too much extra space around, otherwise, they could burn. If you don’t have the right-sized roasting vessel, you might need to split the mixture up among two or three dishes.

Roast the veggies for 30 minutes, then stir/toss and continue to roast for 1.5 hours or until the zucchini and peppers are soft enough to be mashed easily with a fork.

Mash the zucchini and peppers with a fork or a potato masher until they reach the desired level of silky chunkiness. 

Taste for seasoning and adjust with salt if necessary.