Cook the potatoes in boiling salted water for 20-25 mins until tender when pierced with a knife. Meanwhile, heat the 2 tbsp butter in a frying pan over a medium heat until melted, then fry the onion for 10 mins until softened. Stir in the garlic, fry for a minute more, then add the chicken and fry for 5 mins until lightly golden.

Pour in the wine, bring to a simmer and reduce until halved. Stir in 250ml of the crème fraîche. Cook for 5 mins until the chicken is cooked through, and the sauce has thickened slightly.

Drain the potatoes, leave to steam dry for 1 min, then mash with the 50g butter, remaining crème fraîche and some seasoning, until smooth. Stir the herbs and spinach through the chicken and cook for a minute or so until the spinach wilts. Add the lemon juice and some seasoning. Serve spooned over the creamy mash.