Halve 8 regular-sized onions and place cut-side down in a baking dish. Whisk together 100g unsalted butter, 100g white miso paste, and 1 litre warm water, then pour over the onions. Cover and bake for 35 minutes. Flip onions, baste well, and bake uncovered for another 45-50 minutes, basting every 10 minutes until browned and sauce is gravy-like.

Total time: 92m