For the chicken:
1. Place the wine in a saucepan with the stock, garlic, onion, carrot, celery, bay leaves, cloves, peppercorns and lemon peel. Bring to the boil.
2. Place the chicken breasts bone-side down into the stock, bring back to the boil, turn down the heat, cover and simmer for 25 minutes. Remove from the heat and let the chicken stand in the stock for a further 5 minutes. Remove the chicken and let it cool.
3. Strain the sauce and return to the pot. Simmer till it has reduced to more or less 250ml, then remove from the heat.
For the tonnato sauce:
1. Place the tuna with its oil, the anchovies and the parsley stalks in a blender and give it a whizz.
2. Add the yolks with one tablespoon of lemon juice, whizz again until smooth.
3. Now, with the motor running, slowly add the olive oil, and once it is incorporated slowly add the stock.
4. Adjust the seasoning and top up the lemon juice if the sauce needs it.
Plating: Slice the chicken thinly off the bone and overlap the slices on a platter. Spoon over the sauce and garnish with the parsley, capers and lemon juice. Finish with a grind of black pepper.