Rack of lamb with marmalade mustard crumb topping

Ingredients

• 2 7-bone lamb racks, fat trimmed
• salt and ground black pepper
• 60g butter
• 2 tablespoons marmalade or apricot jam
• 1 heaped tablespoon wholegrain mustard
• 1 tea-cup coarse breadcrumbs (or use Japanese panko crumbs for that extra touch)
• 1 small white onion, peeled and thinly sliced
• 2 garlic cloves, peeled and thinly sliced
• 3 tablespoons olive oil or butter
• 2 teaspoons rosemary leaves, roughly chopped
• 1/2 red chilli, thinly sliced (optional)
• 600g baby vegetables (baby carrots, courgettes, sweetcorn and fennel)
• 4 tablespoons pumpkin or sunflower seeds, pinenuts or flaked almonds
• 1 large bunch watercress, washed and drained (optional)
• 2 tablespoons balsamic vinegar