Heat your oven to 240°C.

Halve your onions lengthways and discard the papery skin. Trim any dry tops and carefully trim the base, ensuring that your onion halves remain whole.

Melt your butter in a large pan or in a heatproof bowl in the microwave. Add your miso paste and a litre of warm water, then whisk together until you have a homogenous sauce.

Place your onions cut-side down in a large, high-sided baking tray. Slice up your ginger into thin coins. Pour over your miso water, then add in your ginger and rice before tightly covering it with tin foil. Bake for 35 mins.

Remove your tray from the oven, discard your foil and flip your onions over. Give the onions a good baste with a spoon, then return to the oven. Bake for another 45-50 mins, basting well every 10 mins. Your onions should be deeply golden and soft with gentle charring around the edges. Your sauce will be lovely, thick and golden. After you’ve removed your onions, turn your oven down to 180°C.

Transfer your mixture to a pot with your vegetable stock, stir, and then blitz. Finish with a squeeze of lime juice.

Slice up your bread into rough cubes. Add your cubes of bread to a roasting tray, cover with olive oil and roast for 10 mins. Once they’re looking brown, top with a generous grating of Gruyére and add back into the oven until the cheese is melted.

Serve the soup into bowls, top with your croutons, lime zest, and more olive oil.