Tonnato Dip

To prepare cream sauce: Heat 1 tablespoon oil in a large saucepan over medium heat. Add onion and cook, stirring, until soft but not browned, about 5 minutes. Add rice and cook, stirring, for 2 minutes more. Add broth and wine and bring to a boil. Cover and simmer until the rice is very soft and the liquid is greatly reduced, about 25 minutes. Cool slightly.

Transfer the mixture to a blender and puree, in batches if necessary, until smooth. (Alternatively, puree in the pot with an immersion blender.) The consistency should be similar to a pourable sauce; add more broth or water as needed. Season with 1/4 teaspoon salt and pepper, preferably white pepper.

To prepare dip: Combine tuna (with its oil), 1/2 cup oil, lemon juice, anchovies (or anchovy paste), egg yolk (if using) and garlic in a blender or food processor; process briefly to puree. Transfer to a small mixing bowl and stir in 1/2 cup of the Cream Sauce. Thin with a few tablespoons of water, if desired. Stir in capers and parsley. Season with pepper.