Heat your oven to 200°C/Fan 180°C/Gas 6. Fill and boil your kettle. Scrub the potatoes and halve or quarter them so they’re all roughly the same size. Scatter them onto a baking tray, drizzle with 1/2 tbsp olive oil and a pinch of salt and pepper. Toss to mix, then slide into the oven and roast for 35-40 mins till golden and crisp.

While the new potatoes roast, put a medium-sized pan on a medium heat and add ½ tbsp olive oil. Add the diced chicken leg and fry for 5-6 mins, turning once or twice, till golden all over.

While the chicken fries, peel and finely chop the onion. Peel and grate or crush the garlic.

Lift the golden brown chicken out of the pan and set aside on a plate. Add another ½ tbsp oil to the pan and add the onion. Season with a little salt and pepper. Fry, stirring often, for 5 mins till the onion starts to look glossy.

Drain the butter beans and rinse them. Stir the garlic into the onion. Cook and stir for 1 min. Tip in the butter beans and the chicken, adding any juices from the plate. Stir in 1 tbsp mustard and crumble in the stock cube. Pour in 250ml boiling water, stir to mix, then cover and bring to the boil. Once it’s bubbling, turn the heat down a little and simmer for 10 mins.

Trim the woody ends off the French beans and halve them widthways. Pick the leaves off the tarragon sprigs and roughly chop the leaves.

When the chicken has cooked for 10 mins, stir in the French beans and simmer for 3 mins. Turn the heat down to very low. Then stir in most of the tarragon and half the pot of crème fraîche. Gently warm for 1-2 mins (keeping the heat low helps to stop the crème fraîche form splitting, but if it does split, don't worry. It'll still taste good). Taste and add a pinch more salt or pepper if you think it needs it.

Spoon the creamy braised chicken and beans into 2 warm shallow bowls and serve with the roast new potatoes on the side. Garnish with the remaining tarragon.