Since the beef is served cold, you can roast it a day or two in advance. After roasting, let it cool to room temperature, wrap well and refrigerate until ready to serve. This will also allow the meat to further absorb the pepper flavor.
Recipe courtesy of Williams-Sonoma
- 1 center-cut piece of beef tenderloin, about 3 pounds, well trimmed
- Salt, to taste
- 2 tablespoons coarsely cracked peppercorns
- 4 tablespoons olive oil, plus more for brushing
- 1 baguette, cut into 1/4-inch-thick slices
- Freshly ground pepper, to taste
- 1 red onion, diced
- 1 yellow onion, diced
- 1/4 cup balsamic vinegar
- Chopped fresh tarragon for garnish
- 1 Preheat an oven to 425ºF.
- 2 Using kitchen string, tie the beef at 1-inch intervals along the length of the roast and season generously with salt. Arrange the peppercorns on a large plate in a thin layer and roll the beef in the peppercorns to coat evenly.
- 3 In a large ovenproof fry pan over high heat, warm 2 tablespoons of the olive oil until nearly smoking. Carefully place the beef in the pan and brown 3 to 4 minutes per side.
- 4 Transfer the pan to the oven and roast, turning the beef occasionally, until an instant-read thermometer inserted into the center of the meat registers 125ºF for very rare to rare, about 20 minutes; 130ºF for medium-rare, about 25 minutes; or until done to your liking.
- 5 Meanwhile, reduce the oven temperature to 325ºF.
- 6 In a sauté pan over medium-high heat, warm the remaining 2 tablespoons olive oil. Add the red and yellow onions and sauté, stirring occasionally, until tender and golden, 7 to 10 minutes.
- 7 Add the garlic and sauté, stirring occasionally, until fragrant, 1 to 2 minutes more.
- 8 Add the vinegar and cook, stirring often, until the liquid is nearly evaporated, 3 to 5 minutes more. Season with salt, remove from the heat and let cool to room temperature. Cover and refrigerate until ready to serve.
- 9 To serve, slice the beef crosswise into very thin slices (about 1/8 inch thick). Arrange the crostini on a serving tray, and top each with a slice of beef and 1 to 2 teaspoons of the caramelized onions. Garnish each with a pinch of tarragon.