Tacchino Tonnato (Turkey With Tuna Sauce)

Directions

1. 1
   If you want nice, even slices it's a good idea to roll or shape and then tie the turkey breast with kitchen string, as for a roast - it cooks more evenly this way too. Sprinkle with salt and pepper.
2. 2
   Peel and cut the onion in half, and then in thin slices. Add to a deep, heavy bottomed pot with the olive oil and heat gently. Let the onions sweat, cooking on low heat until softened but not browned, about 10 minutes.
3. 3
   Add the tuna, drained of any liquid, then add the turkey. Turn heat up slightly and sear turkey on all sides.
4. 4
   Add the wine (or water) and turn heat up. When it comes to a boil, turn down to a simmer and let cook for 1 hour, turning the turkey about halfway and at this point, covering with a lid to finish cooking - there should still be sufficient liquid in the pot that it arrives at least halfway up the turkey.
5. 5
   Remove the turkey from the pot and set it aside. Drain the tuna and onions from the liquid in the pot and set aside the liquid. Blend the tuna and onions with an immersion blender (or similar), adding the anchovy fillets and the boiled eggs, until very smooth and thick. If too thick, add some of the liquid slowly until the sauce loosens. Taste for seasoning and add salt and pepper as needed.
6. 6
   Serve the turkey sliced, with the sauce poured over and sprinkled with capers (a must) and parsley, if desired. This is lovely warm or cold.
7. 7
   If you would like to make just the sauce, say, to use with some left over turkey or another roast, simply sautee the onion in olive oil, add it to the tuna, anchovies and boiled eggs in a blender or food processor, adding a few tablespoons of mild olive oil, a dash of white wine vinegar or water (the combination of oil and water will help make an emulsion) until you have a thick, creamy sauce.