1.Drain chickpeas in a sieve over a small bowl; reserve liquid (aquafaba). Rinse chickpeas. Place chickpeas and oil in a large bowl; coarsely mash with a fork. Add ½ cup of the breadcrumbs, the flour, sauce, garlic, ras el hanout, xanthan gum and iced water;season. Mix well using clean hands.
2.Grease two large oven trays; line with baking paper.
3.Divide chickpea mixture into eight portions; shape into balls. Place four balls, spacing them apart, on each tray. Using the palm of your hand, press down into 8mm (⅓in) thick, rough oval shapes. Freeze for 1 hour or until very firm.
4.Working quickly, dip chickpea schnitzels in reserved aquafaba, then carefully coat in combined remaining breadcrumbs and sesame seeds. Return coated schnitzels to trays; freeze for 20 minutes to firm or until required.
5.Meanwhile, make winter slaw. Trim and separate sprout leaves. Drop leaves into a large saucepan of boiling salted water until bright green; drain. Drop into a bowl of iced water until cold; drain well. Transfer to a large bowl. Meanwhile, using a mandoline or V-slicer, thinly slice fennel, celery and onion. Add to bowl with sprouts, then add parmesan; toss gently to combine. Whisk juice, honey and mustard in a small bowl until combined. Gradually add oil, whisking constantly, until well combined; season to taste. Just before serving, add dressing to slaw; toss gently to coat.
6.Heat half the vegetable oil in a large non-stick frying pan over medium heat; cook schnitzels, in two batches, 4 minutes each side or until golden and crisp, adding remaining vegetable oil in between batches. Drain on paper towel.
7.Combine aïoli, capers, celery leaves and fennel leaves in a small bowl; top with extra fennel leaves.
8.Serve schnitzels with winter slaw and aïoli mixture.
Xanthan gum is sold in powder form in the health food section of supermarkets; it is a gluten-free thickening agent. Reserve the leaves from the fennel and celery in
the winter slaw to combine with the aïoli in step 7.