Roasted Mackerel, Dashi Gelée, Roasted Eggplant, Crosnes, Dahlia Bulb, Pickled Nasturtium Berries, Radicchio, and Radishes

In a stock pot, combine water, carcasses, mirepoix, kombu, paprika, and sardines. Bring to boil, lower heat, and simmer until stock is flavorful and aromatic, about 30 minutes. Strain into a pot containing bonito, katsuobushi, and sakura. Cover and steep until stock is rich and aromatic, about 30 minutes, tasting every 10 minutes. Strain into another pot. In a bowl, whisk together egg whites and miso until mixture forms soft, frothy peaks. Whisk mixture into stock. Place pot over medium heat and clarify stock. Strain consomm through chinois lined with cheesecloth. Taste and adjust seasoning. Consomm should be rich and complex. Scale and record weight of consomm; keep warm. Pour a small amount of consomm into a saucepan and bring to boil. Add 1% by weight agar agar. Boil 3 minutes. Pour agar mixture into pot with the consomm. Stir to combine. Add gelatin, stirring to combine. Pour into a nonreactive container and allow to set for at least 4 hours or refrigerate overnight. Slice into batons.

Lay mackerel in a nonreactive container. In a bowl, combine remaining ingredients. Cover mackerel in salt-herb mixture. Cure for 8 hours or overnight, as with gravlox. Gently rinse and drain mackerel.

In a hot cast iron pan, heat oil, and add mackerel skin-side-down, followed by eggplant, crosnes, radicchio, and radish. Allow mackerel to char on skin side. Transfer mackerel to cutting board. Slice into 4 portions and arrange on serving plates. Garnish with remaining contents of pan and with dahlia bulb and nasturtium berries. Finish with a few batons of Dashi Gelée.