Cut into small pieces and place in the freezer:
Melt in a large skillet over medium heat:
Add:
Cook, stirring, until softened, 2 to 3 minutes. Add:
Cook, stirring constantly, until softened, about 3 minutes. Transfer to a food processor. Rinse and pat dry:
Heat in the same skillet over medium-high heat until the foam subsides:
Add the chicken livers and season with:
Cook until browned on the outside but still pink in the center, about 2 minutes on each side. Remove the skillet from the heat. Pour in:
Ignite with a long match or lighter. Return the skillet to the heat and swirl until the alcohol has burned off. Add to the food processor. If desired, also add:
Process until smooth. With the machine running, drop in the pieces of chilled butter one at a time. Taste and adjust the seasonings. Scrape into a small crock or bowl and smooth the top with a spatula. Press plastic wrap directly on the surface and refrigerate until firm, at least 2 hours. Serve cold or at room temperature.