Cut the salmon slanting as possible or even lengthwise if possible, meanwhile in a bowl mix well the tuna and ricotta, season and place on the salmon fillet. Roll the salmon, place on an oven tray and grill roast until cooked through. Finely slice the fennel and sauté in butter on low heat, add a little stock season and allow to cook though. Chop the leeks, garlic and sauté in butter until butter is browned. Add the stock and simmer to reduce by half, add the cream and simmer for a few more minutes, whisk in the dill and a knob of salted butter.