Peel the zucchini, cut into cubes and fry together with the finely chopped onion, the crushed garlic cloves, four tablespoons of olive oil and a little salt until they disintegrate. This takes 20 to 30 minutes. Then the zucchini are mashed with a fork and simmered over low heat until the liquid has evaporated completely.
Let the puree cool and put in the fridge for a few hours. Then mix with the ricotta, the chopped basil and the chopped coriander leaves. Season to taste with a little salt and pepper. At the end, mix in a tablespoon of olive oil and a splash of lemon juice.
The puree tastes great on crostini or as an accompaniment to grilled food.