Reserve the bay leaves and sprigs of rosemary, thyme, the duck breast and the skin. Take out the parsley stems and carrot pieces if you are mincing by hand. Cut these very fine or run these through a kitchen machine
Place the meat pieces for 15-20 minutes on a tray in the freezer and then run it all through the meat grinder including the juices if any. Do this three times and run it through the course blade only. The freezing will make it easier to mince the meat pieces, especially when using a hand mincer. Keep the mixture cool at all times
Cover a terrine on the inside with the fatty duck skin that was not marinated (skin side down and to the outside) or use some bacon for the same purpose. The fat from the skin will keep the pate moist and also will have a preserving effect
Add to the minced meat the (optional) shredded walnuts and the breadcrumbs
Take the egg and briefly homogenize with the whisk. Mix the egg with the minced mixture as well.
Take a sample and spread on a plate, microwave it quickly and let it cool down and taste to check on the spices and saltiness. Bring the minced mixture to taste with some more salt, pepper and other spices if so needed.
Then make a final pass through the mincer (the fourth time) to homogenize and emulsify
Scoop the minced meat, shredded parsley, onion and carrot mixture in the terrine and at 40 % filling level place the skinned duck breast as a whole in there. Thereafter add more minced mixture and cover with a reserved piece of bacon and some herbs (eg the reserved bay leaves and/or some rosemary or thyme sprigs)
Cover the terrine with parchment paper and use aluminum foil as a lid if there is none and place in a large pan or wok that is filled with near boiling water, to a water level of 60% of the terrine. Place this pan on low fire and keep the water close to a boil 194-208 F (90-98 C)
After 90 minutes, remove the cover and measure the inside temperature. This should be at least 162 F (72 C) when using pork liver. If not yet reached, continue to ‘cook’ it in the water bath until the inner temperature is right. Molten fat is clearly visible floating on top of the terrine and the smell is already very nice
Let the terrine cool down at room temperature. While this is happening, place a tight-fitting piece of cardboard that is covered with aluminum foil on top of the parchment paper sheet. Place weights on it and let cool down for 2 hr
Thereafter place in the refrigerator overnight with the cover and weights on. (use canned food as weights)