Bring a medium saucepan of salted water to the boil for the vegetables. Quarter the unpeeled potatoes. Coarsely chop the carrot. Crush or finely chop the garlic. Cut the fish into 3cm-thick strips.
Step 2 — Crumb fish
Whisk 1 egg in a shallow bowl. Add the garlic, season with salt and pepper and stir to combine. Put the breadcrumbs in a separate shallow bowl. Dip the fish in the egg mixture, then lightly coat in the breadcrumbs.
Step 3 — Cook vegetables
Cook the potato and carrot in the pan of boiling water for 12 mins or until just tender. Add the peas and cook for a further 2-3 mins until tender. Drain, then return to the pan.
Step 4 — Cook fish katsu
Meanwhile, heat 2 tbs olive oil in a medium frypan over medium heat (see Kitchen hack). Cook the fish for 4 mins each side or until golden and cooked through. Remove from the pan and drain on paper towel.
Step 5 — Serve up
Coarsely mash the vegetables with a potato masher. Add 2 tsp olive oil, season with salt and pepper and stir to combine. Divide the mash among plates, top with the fish katsu, then drizzle with the tonkatsu sauce. Enjoy!
Step 6 — Kitchen hack
Instead of pan-frying, put the crumbed fish on a lined oven tray, spray with olive oil and bake at 200C for 14-16 mins until golden and cooked through.