To a large stainless steel pan, add 1 tbsp of rapeseed oil and preheat the pan over a high heat. Once hot, add the chicken breast and season with salt and pepper. Leave to sear/cook for 4-5 minutes on one-side, or until you can flip the chicken without it sticking.
Meanwhile, in a separate pan fry the courgettes with a decent pinch of salt and pepper and 1 tbsp of rapeseed oil. Fry, stirring occasionally for around 8 minutes.
Rotate the chicken pieces and cook for 2 more minutes. Set aside (the chicken won’t be fully cooked yet). Deglaze the pan with a splash of stock and reduce the heat to medium/low. Add the onion with a pinch of salt and pepper.
After 4 minutes of frying, add the garlic. Fry for a couple of minutes, then add the cream and tarragon. Once the cream is heated through, slowly pour the stock into the pan whilst stirring continuously.
Add the cornflour slurry and white wine vinegar into the pan and stir. Then add the seared chicken breast back into the pan and cook over a low/medium heat for 5 more minutes, or until the breast is fully cooked.
Remove from the heat and top with fresh basil to serve. Serve with a side of sauteed courgette and enjoy!