1 - In a jug, mix the tahini with the zest and juice of the lemon and 50ml of cold water to make a runny dressing.

2 - Season to taste, then set aside.

3 - Heat the oil in a wok or large frying pan over a medium-high heat.

4 - Add the red onion, along with a pinch of salt, and fry for 2 mins until starting to soften and colour.

5 - Add the garlic, pepper, green beans and courgette and fry for 5 min, stirring frequently.