The dressing and puree can be made ahead of time, then used to assemble the salad at serving time.
Put all dressing ingredients except for the maple syrup into a small blender (I used a stick blender in an upright blending jar). Blend until perfectly smooth, then taste and adjust sourness by adding 1-2 tsp maple syrup, if desired. Set aside until serving time.
To make the puree, heat olive oil in a frypan (skillet) over medium heat. Add onion and cook, stirring often, for around 10 minutes or until deeply caramelised. Add garlic for the final 1-2 minutes of cooking time. Remove from the heat and allow to cool a little.
Put caramelised onion mixture, butter beans, mustard, salt and 2 tbsp of water into a blender or food processor. Blend until fairly smooth, stopping to scrape down the sides as needed. You may like to add another 1-2 tbsp of water to achieve a thick but smooth consistency. Set aside until serving time.
To make the salad, trim ends from the zucchini then use a vegetable peeler or mandoline to slice the zucchini into thin ribbons lengthwise. Drain artichokes and slice each piece in half, if you like. If using natural macadamias, toast in a dry frypan for about 5 minutes until coloured in places. Toss zucchini ribbons, artichokes, macadamias and dressing together in a mixing bowl.
To serve, smear a generous scoop of bean puree onto a plate, then top with a jumble of salad and a sprinkle of lemon zest. For a more substantial meal, serve with grilled pita bread.