Prepare the vegetables. Finely chop the onion and garlic and fry until caramelized in a frying pan with butter.
Prepare the liver. Melt 70 g of butter in a saucepan, add the chicken liver, and simmer for about 8 minutes. The offal should be white on top and pink inside. Season with salt and pepper, add spices. Pour in the cognac and continue simmering for 5 minutes. Pour in the cream, stir, and cook for 10-12 minutes, covering the saucepan with a lid. 2-3 minutes before the end of cooking, add the onion-garlic mixture and stir the contents.
Finish the parfait. Use a blender to beat the liver with the spices and vegetables. You should get a smooth, homogeneous mass. Transfer the mass to a mold and pour melted butter on top.