Place a rack in the middle of the oven and preheat it to 210 °C / 410 °F. Cut the bread into thin slices. Arrange on top of a large baking sheet lined with parchment paper in a single layer. Bake for 10 minutes or until crunchy.
Add butter to a pan and place over medium heat. Peel the onion and shallot and cut them into thin slices. Add to a pan along with chopped herbs. Sauté for 6 - 8 minutes over medium heat or until the onion is caramelized. Clean the chicken liver, trim any fat or connective tissue, and discard them. Increase the heat and add the chicken liver to the pan. Pan-fry for 3 - 4 minutes on high heat. Add the cognac and flambé, or cook for 1 minute for half of the liquid to evaporate. Remove from the heat. The liver should still be slightly pink in the middle.
stir to combine
Transfer the mixture to a food processor. Add the heavy cream and season with salt, pepper, ginger, and allspice. Mix into a smooth mixture. Add the cubed butter and stir into a smooth mixture. Strain the pate through a sieve to get rid of any tissue and to get a creamy, smooth pate.
Add the chicken liver pate to a serving bowl—and place in the fridge for 15 minutes for the pate to harden a little bit. Pour the melted butter on top and return to the refrigerator for 4 - 6 hours or overnight. Optionally freeze the pate for up to a month.