Preheat your oven to 220°C/200°C fan/gas mark 7.

Chop the potatoes into 2cm chunks (no need to peel). Pop them onto a large baking tray. Drizzle with oil, season with salt and pepper, then toss to coat. 

Spread out in a single layer. TIP: Use two baking trays if necessary. 

When the oven is hot, roast on the middle shelf until golden, 30-40 mins. Turn halfway through.

Meanwhile, peel and grate the garlic (or use a garlic press).

Pick the tarragon leaves from their stalks and finely chop (see ingredients for amount, discard the stalks).

Sandwich each chicken breast between two pieces of baking paper or cling film. TIP: Notice a stronger smell from your chicken? Don’t worry, this is normal due to packaging we use to keep it fresh.

Pop onto a board, then give them a bash with a rolling pin or the bottom of a saucepan until they're 1-2cm thick. IMPORTANT: Wash your hands and equipment after handling raw chicken and its packaging.

When the potatoes are about halfway through cooking, heat a drizzle of oil in a large frying pan on medium-high heat.

Season the chicken with salt and pepper, then lay them into the pan. Cook until browned, 3-4 mins each side. 

Transfer the chicken to a baking tray and roast on the top shelf of your oven until the chicken is cooked, 8-10 mins. IMPORTANT: The chicken is cooked when no longer pink in the middle.

Meanwhile, pop the (now empty) frying pan back on medium-high heat with a drizzle more oil (no need to clean).

Add the spring greens along with the water (see pantry for amount). Cover with a tight-fitting lid and cook until wilted, 2-3 mins.

Add the peas and stir-fry for 1 min more, then season with salt and pepper. Transfer to a bowl and cover to keep warm. 

Pop the frying pan back on medium heat with a drizzle more oil if needed. 

Once hot, add the garlic and fry for 1 min.

Stir in the creme fraiche, chicken stock paste and water for the sauce (see pantry for amount). Bring to a simmer and bubble gently until the sauce has thickened, 2-3 mins.

Remove from the heat, then stir through the tarragon.

When everything's ready, thinly slice the chicken widthways and transfer to your plates.

Reheat the tarragon sauce if necessary and add a splash of water if it's a little too thick, then spoon it over the chicken.

Serve the roasted potatoes and veg alongside.