Heat the oil in a frying pan, preferably non-stick. Add the chicken and fry without moving it until it takes on a bit of colour. Turn the chicken and cook on the other side. Continue cooking for 12-15 mins until the chicken is cooked through. Season all over with a little salt and pepper.
Halve the tomatoes and throw them into the pan, stirring them around for a couple of minutes until they start to soften. Reduce the heat and stir in the pesto and crème fraîche until it makes a sauce. Scatter with a few basil leaves if you have them, then serve with rice and salad or mash and broccoli.