Wrap each chicken breast in two rashers of bacon, winding them around the chicken diagonally. Lay in an ovenproof dish leaving a 1cm gap between each fillet so they cook evenly.
Blend the sauce ingredients together in a bowl with a hand blender (or in a food processor) and pour over the chicken. This can be done in advance and stored in the fridge until cooking.
Bake in the oven for 45 minutes, uncovered, or until the chicken is tender and the sauce is piping hot. Every 15 minutes or so, spoon some of the juices over the chicken to ensure it doesn’t dry out. When cooked, stir the crème fraîche into the sauce and season to taste.