Instructions
Step 1
Position a rack in the center of the oven and preheat to 425°F. Season the veal with salt and black pepper to taste, then drizzle lightly with extra-virgin olive oil and rub evenly to coat. Place on a rimmed baking sheet and roast until a meat thermometer inserted into the center of the thickest part of the meat reads 140°F, about 30 minutes. (The meat will still be quite rare.)
Step 2
In a large skillet, heat 1 tablespoon of the light olive oil over high heat until slightly smoking. Add the veal and cook, turning occasionally, until browned on all sides, about 5 minutes. Transfer to a large platter and refrigerate for at least 1 and up to 24 hours.
Step 3
Meanwhile, to the cup of an immersion blender or the bowl of a small food processor, add the lemon juice, mustard, vinegar, caper berries, anchovies, egg yolk, and garlic, followed by the remaining light olive oil. Pulse until all of the oil has emulsified. Add the tuna and continue pulsing until a smooth sauce forms. Transfer the sauce to a medium bowl, then slowly drizzle in ¼ cup of extra-virgin olive oil while whisking continuously until all of the oil has emulsified. Season to taste with salt, black pepper, and more lemon juice.
Step 4
On a large cutting board, thinly slice the veal against the grain. Spoon the tuna sauce in an even layer over a large platter, then arrange the veal slices over it. (If you like, you may cover and refrigerate for up to 8 hours to allow the flavors to meld.)
Step 5
When ready to serve, top the veal with celery and parsley leaves, sliced radishes, a drizzle of extra-virgin olive oil, caper berries, and a sprinkle of salt. Serve cold or at room temperature.