• Make-Ahead

Ingredients

1. 1 1/4 pounds chicken livers, trimmed, at room temperature
2. 8 large egg yolks, at room temperature
3. 2 tablespoons brandy
4. 2 tablespoons Calvados or other apple brandy
5. 1 tablespoon salt
6. 1 1/2 teaspoons freshly ground white pepper
7. 3/4 teaspoon ground allspice
8. Pinch of freshly grated nutmeg
9. 3 sticks (3/4 pound) unsalted butter, cut into tablespoons, at room temperature
10. 2 cups heavy cream
11. Toasted baguette slices, for serving
12. Sweet-and-Sour Red-Onion Relish, for serving 

Directions

1. Preheat the oven to 275°. In a food processor, combine the livers, egg yolks, brandy, Calvados, salt, pepper, allspice and nutmeg and puree until smooth. With the machine on, blend in the softened butter, 1 tablespoon at a time, until all the butter is incorporated and the puree is creamy; if it looks curdled, wrap a hot kitchen towel around the processor bowl and puree until light and creamy.
2. Pass the puree through a fine strainer set over a large bowl and stir in the heavy cream until blended. Pour the puree into a 1 1/2-quart enameled cast-iron terrine and set the terrine in a roasting pan. Pour enough boiling water into the roasting pan to reach halfway up the side of the terrine and bake for 1 hour and 10 minutes, or until the mousse is lightly browned on top and a toothpick inserted in the center comes out clean. Remove the terrine from the water bath and let cool, then cover with plastic wrap and aluminum foil and refrigerate overnight.
3. To unmold, dip the bottom of the terrine in a pan of hot water for 10 seconds, and run a paring knife around the edge of the mousse. Invert the mousse onto a long platter or rectangular plate. Cut it into 1/2-inch slices and transfer to plates. Serve with baguette toasts and the Sweet-and-Sour Red-Onion Relish.

Make Ahead

The mousse can be refrigerated in its terrine for up to 1 week; place plastic wrap directly on its surface. Leftovers can be tightly wrapped in plastic and refrigerated for up to 5 days. Let stand at room temperature for 30 minutes before serving.