Remove 50g butter from the fridge to soften. Peel and finely grate the ginger. Peel the sweet potatoes, then cut into 2cm chunks. Discard the husk and silks from the corn, then cut into 4 cobettes. Trim the beans. Finely grate the zest of half the lime*, then juice the half.
Step 2 — Prep chicken
Put the chicken flat on a board, put your hand on top and halve horizontally into fillets. Put the mirin, half the ginger and 1 tbs soy sauce in a shallow dish, season with pepper and stir to combine. Add the chicken and turn to coat.
Step 3 — Make mash
Put the sweet potato in a small saucepan, cover with cold salted water and bring to the boil. Reduce heat to medium and cook for 12-14 mins until tender. Drain, then return to the pan. Add the remaining ginger and 10g butter and mash until smooth. Season with salt and pepper and cover to keep warm. Bring a medium saucepan of water to the boil for the vegetables.
Step 4 — Cook chicken
Meanwhile, heat 2 tsp oil in a medium frypan over medium-high heat. Remove chicken from the marinade, reserving marinade. Cook the chicken for 2-4 mins each side until golden and cooked through. Remove and rest for 3 mins. Reduce heat to medium, add reserved marinade to the pan and cook, stirring, for 1 min or until slightly reduced to a thin glaze. Remove from heat.
Step 5 — Cook vegetables
While the chicken is cooking, cook the corn in the pan of boiling water for 5 mins. Add the beans to the corn and cook for a further 3 mins or until the vegetables are tender. Drain and return to the pan.
Step 6 — Make miso butter
Put the miso, lime zest, lime juice and 40g soft butter in a bowl and mash with a fork to combine. Add the miso butter to the vegetables and toss to coat. Divide the mash, chicken and vegetables among plates. Drizzle the glaze over the chicken to serve.