1. On a paper-lined sheet pan, lightly salt the mackerel fillets, cover with plastic wrap and refrigerate for 2 hours.
2. In a food processor, pulse and grind the fillets into a coarse paste. Transfer into a bowl and set aside.
3. Blanch the shavings of burdock root in the all-purpose dashi stock, drain and set aside.
4. Pulse the cod or pollock in a food processor, gradually adding 1/3 cup of the dashi stock. Add sake, sugar, soy sauce and white miso, then give a few more pulses. Transfer the mixture into a large bowl. Add the aji horse mackerel paste, the egg-oil mixture (tamamoto) and the burdock shavings. Mix well with rubber spatula. Make 12 oval cakes, about 2/3 inch (1.5cm) thick. Lay on a sheet pan lined with parchment paper, cover tightly with plastic wrap and refrigerate for 20 minutes.
5. To deep fry: In a large heavy saucepan, heat the oil to 340° F (170° C). Deep fry the cakes until golden brown, about 4-5 minutes. Transfer to a paper-lined plate to drain excess oil.
6. To serve: Cut each cake into quarters and arrange on a plate with the grated ginger and wasabi on the side. Serve soy sauce in individual small dishes for dipping the cakes.
All-purpose dashi stock (happo dashi)
- 1 quart (1L) dashi stock (see below)
- 1/4 cup (60ml) soy sauce
- 1 tsp sea salt or to taste
Combine all ingredients in a large bowl or container. Ladle out as needed.
Dashi is the basis of Japanese soups, stews, stock concentrates and sauces, and the better your dashi, the more successful your meal will be. Powdered instant dashi is readily available, but it is simple to make your own - and avoid the additives often contained in those products.
The more refined dashi uses katsuo bonito flakes, which are not cheap, but excellent results can be had with niboshi dried small sardines, or ago flying fish. These produce a smokier flavor, which may be just what you want, especially in soup noodle dishes.
To make about 1 quart (1L) dashi stock: heat 1 quart (1L) water until tepid (86° F/30° C), then add in three 2x3 inch (5x7.5cm) strips of kombu kelp (about 0.7 oz/20g). Bring slowly to a simmer over 20-30 minutes. When simmering, immediately remove the kombu, skim the scum from the surface and bring to a boil.
Add 1/4 cup (60ml) of cold water to quell the bubbles and immediately lower the heat. Add in 2 oz. (60g) bonito flakes. When all bonito flakes have soaked up the liquid and the liquid has barely returned to the boil, turn off the heat. Leave for five minutes and strain through a sieve lined with a fine cloth, or a large coffee filter. Cool at room temperature without covering.