Preheat the oven to 375°F. Heat the olive oil in a large ovenproof skillet over medium-high heat. Season with chicken breasts lightly with salt and pepper, then wrap 2 slices of ham around each chicken breast. Add to the pan and cook for about 4 minutes per side, until the ham is golden and crispy. Transfer the pan to the oven and cook for 12 to 15 minutes, until the chicken is cooked through.
Meanwhile, combine the basil, crème fraiche, and lemon juice in a blender and blend until smooth. Season with salt and pepper, to taste. Spoon the sauce over the chicken breasts and serve.