Preheat the oven to 325°F (160°C). Lightly oil a 2–3 lb terrine or loaf pan and line it with overlapping slices of Streaky Bacon, leaving an overhang to fold over the top later.
Soak 4–6 slices of Country Bread in a bowl with Whole Milk until softened, then squeeze out excess milk and set the soaked bread aside (reserve a little milk).
Trim excess sinew from the Pork Shoulder and Pork Belly and cut into 1-inch cubes; coarsely chop the Pork Liver as well. Chill the meat briefly so it grinds cleanly.
Finely mince the Shallots and Garlic. In a skillet over medium heat, sweat the shallots and garlic in a little oil until translucent and fragrant; cool slightly.
Toast and lightly crush the Juniper Berries and remove the leaves from the Thyme Leaves; chop the Flat-Leaf Parsley. Add these aromatics to the cooled shallot mixture.
Working in batches, pulse the pork shoulder, pork belly and liver through a coarse grinder (or use a food processor with short pulses) to achieve a rustic, slightly chunky texture. Return the meat to a large mixing bowl.
Tear the soaked bread and add to the meat along with the shallot-herb mixture, a splash of the reserved milk, Eggs, a couple of tablespoons of Heavy Cream, and a generous measure of Cognac; mix until evenly combined but not puréed.
Season the mixture with Fine Sea Salt, freshly ground Black Pepper, a pinch of Quatre Épices and a very small amount of Pink Curing Salt if using (follow package guidance)—taste a small cooked piece to adjust seasoning.
Spoon the mixture into the bacon-lined terrine, pressing down firmly to eliminate air pockets. Smooth the surface, fold the bacon over to cover, and tuck a couple of Bay Leaves on top before sealing the terrine with foil or a lid.
Place the terrine in a roasting pan and pour hot water into the pan to come halfway up the sides of the terrine. Bake in the preheated oven until the center reaches about 160°F (71°C), about 60–90 minutes depending on size.
Remove the terrine from the water bath and let it cool to room temperature. Place a weight on top to compact the pâté, then refrigerate for at least 12–24 hours to firm and develop flavor.
To serve, unwrap and invert the terrine. Slice with a sharp knife and accompany with additional slices of Country Bread, Cornichons and a dollop of Dijon Mustard.
