Japanese Aji Fry and Menchi Katsu: Breaded Fried Preparations Beyond Tonkatsu

Ingredients

• For the aji fry
• 4 horse mackerel (aji), scaled, gutted, butterflied by sanmai-oroshi three-piece fillet technique, tail fin left on
• 60 g plain flour, for dusting
• 2 eggs, beaten
• 120 g fresh panko breadcrumbs
• For the menchi katsu
• 250 g minced pork
• 250 g minced beef
• 1 medium onion, finely chopped
• 1 egg, beaten, for binding
• 40 g breadcrumbs, for binding the meat mixture
• 60 g plain flour, for dusting
• 2 eggs, beaten, for coating
• 120 g fresh panko breadcrumbs, for coating
• For the kani cream croquette
• 500 ml whole milk
• 50 g unsalted butter
• 50 g plain flour, for the béchamel roux
• 200 g crab meat, or imitation crab, picked and flaked
• 60 g plain flour, for dusting the croquettes
• 2 eggs, beaten, for coating
• 150 g fresh panko breadcrumbs, for coating
• For frying and service
• 1.5 litres neutral oil, vegetable or rice bran, for deep-frying at 175–180°C
• to taste Worcestershire-Bulldog sauce, for service with menchi katsu

Method

1. 1
   AJI FRY — BUTTERFLY THE FISH. Apply the sanmai-oroshi three-piece fillet technique: remove the backbone from each scaled, gutted fish, leaving both fillets joined at the belly and the tail fin intact. Open the fish flat. The butterflied form must present equal thickness throughout — this is the structural logic of aji over thicker fish, preventing raw centres and overcooked edges in the same piece.
2. 2
   AJI FRY — BREAD AND FRY. Dust each butterflied fish in flour, dip in beaten egg, and coat in fresh panko, pressing lightly to adhere. Heat neutral oil to 180°C. Lower the fish into the oil and fry until the panko crust is deeply golden and the tail fin has crisped to a rigid, translucent frond — the visual and tactile signals that the fish is cooked through.
3. 3
   MENCHI KATSU — BIND THE MIXTURE. Combine minced pork, minced beef, finely chopped onion, beaten egg, and breadcrumbs in a bowl. Work the mixture until fully cohesive. Divide into four equal patties. The mixture must be firmly bound — insufficient binding causes the patty to rupture in the oil, producing dangerous fat splattering. Refrigerate the formed patties for 30 minutes; they should feel firm and hold a clean edge when lifted.
4. 4
   MENCHI KATSU — BREAD AND FRY. Dust the chilled patties in flour, dip in beaten egg, and coat in fresh panko. Heat oil to 175–180°C. Fry until the crust is uniformly deep golden and the patties feel set when pressed with tongs — no yielding at the centre.
5. 5
   KANI CROQUETTE — BUILD THE BÉCHAMEL CORE. Melt butter in a heavy saucepan, add flour, and cook the roux until it smells faintly nutty. Add whole milk gradually, whisking without pause, until the sauce is very thick — substantially firmer than a pouring béchamel. Fold in the flaked crab. Spread onto a tray, cover flush with film, and refrigerate until fully cold and set.
6. 6
   KANI CROQUETTE — FORM AND FREEZE. Portion the cold béchamel into cylinders of equal size. Place on a lined tray and freeze for a minimum of 2 hours. The core must be frozen solid before breading proceeds — room-temperature or merely chilled béchamel will leak at first oil contact, collapsing the croquette entirely. This is where the dish lives or dies.
7. 7
   KANI CROQUETTE — BREAD AND FRY. Working directly from the freezer, dust each frozen cylinder in flour, dip in beaten egg, and coat in fresh panko. Return immediately to fry at 180°C for exactly 4 minutes. The crust should be a uniform amber-gold; the interior, audible as it is lifted, will have thawed and liquefied inside the sealed shell.