Ingredients
- 8 regular-sized onions 1.2kg
- 100 g unsalted butter melted
- 100 g white miso paste
Instructions
- Preheat the oven to 240°C fan.
- Halve the onions lengthways, discarding the papery skin, as well as the layer beneath if it is tough or dry. Trim the tops, and a little off the bottom (not too much – you want to ensure the onion halves stay held together at the base).
- Whisk the melted butter, miso and 1 litre of warm water together until fully combined.
- Place the onion halves, cut side down and spaced apart, in a 40cm x 28cm high-sided baking tray or dish and pour over the miso water. Cover tightly with foil and bake for 35 minutes, then remove the foil and turn the onions over so they are cut side up (take care to ensure they remain intact). Baste the onions very well, then return to the oven, uncovered, for another 45–50 minutes, basting every 10 minutes, until the onions are very soft, deeply browned on top, and the sauce has reduced to a gravy consistency.
- Carefully transfer the onions to a platter, pouring the sauce over and around them, and serve at once.
Notes
The tray should be just big enough to fit the halved onions in a single layer, without them overlapping. The onions will then shrink as they cook, creating the space the sauce needs to evaporate and thicken into a glorious gravy. If your tray isn’t big enough to fit eight onions (that’s sixteen halves), then roast fewer, decreasing the rest of the ingredients proportionally (the cooking method and time stay the same). It’s also important to saturate each onion half very well every time you baste, spooning the sauce over several times so the cut sides remain moist. This is to ensure that the onions caramelise, rather than burn.
