Chicken dishes are often the “conservative” option on restaurant menus and can be a little bland. This, however, is a very flavourful recipe that can be served with simple mashed potatoes, pasta, risotto, or even a salad.
In a wide-bottomed pot, combine onions, garlic, shallots, oil, butter, salt and pepper and cook for 90 minutes to caramelize onions. Start the onions over high heat and then turn it down to very low, stirring frequently to prevent sticking. When onions are dark and sticky, add sherry and deglaze the pan. Remove onions and allow them to cool in a mixing bowl. Add ham, cheeses, breadcrumbs, and chives and mix thoroughly. Place stuffing in a piping bag with a wide-mouthed round pastry tip.
To prepare chicken breasts, insert the blade of a paring knife into the thickest part, near the bone end. Hold breast flat against the work surface as you insert the blade, and with a sweeping motion create a cavity for the stuffing. Fill each breast with as much stuffing as possible. Close the cavity with a toothpick and roast at 425ºF (215ºC) for 12 minutes. Rest chicken for 10 minutes and then slice on the bias through the centre of the breast, exposing the soft filling.