- 2 large eggs, separated
- 9 ounces cooked ham, trimmed and finely ground in a food processor (2 cups)
- Pinch of freshly grated nutmeg
- Pinch of white pepper
- Pinch of cayenne
- 1/2 teaspoon salt
- 1 cup chilled heavy cream
- 2 tablespoons medium-dry Sherry
- Garnish: watercress sprigs
- Accompaniment: Hollandaise
- Special equipment: an 8- by 4- by 2 1/2-inch (1-quart) metal loaf pan
- Preheat oven to 300°F.
- Whisk yolks in a bowl, then whisk in ham, nutmeg, white pepper, cayenne, and salt.
- Beat together cream and Sherry in another bowl with an electric mixer until cream holds soft peaks, then fold into ham gently but thoroughly.
- Beat egg whites with a pinch of salt in another bowl with cleaned beaters until frothy, then fold into ham gently but thoroughly.
- Spread mousse in well-buttered loaf pan and bake, uncovered, in a hot water bath in middle of oven until a toothpick inserted in center comes out clean and mousse is firm to the touch, about 1 1/2 hours.
- Transfer loaf pan to a rack and cool mousse 40 minutes. Run dull side of a thin knife or a small spatula around edges and invert mousse onto a plate.