Heat the oven to 200C/fan 180C/gas 6. Make a pocket in the chicken breast by cutting into the thickest part, from the side, being careful not to cut all the way through. Repeat with the other chicken breast. Mix together the goat’s cheese, pesto and lemon zest with a little seasoning, and stuff this into the pockets you’ve made in the chicken. Season the chicken generously, lay out the prosciutto slices and use these to wrap each breast. Put both onto a baking-paper-lined tray and roast for 20-25 minutes.