The lovechild of a classic Welsh rarebit (also spelt rabbit!) and the delicious Indian masala cheese toasts from the bustling city of Mumbai, our Legendary Mumbai Rarebit includes some tangy pickled onions that perfectly balance the richness of the cheese topping.

• 1 small red onion - very thinly sliced
• 25g butter
• 125ml milk (any type)
• 200g cheddar cheese - coarsely grated
• 25g plain flour
• 1 tbsp vinegar (malt or cider vinegar is best)
• 4 large slices of thickly cut bread