Pork Tenderloin With Arugula Endive and Walnut Vinaigrette

Preparation

1. Step 1

   Preheat oven to 375°F with rack in middle.

   Step 2

   Pat pork dry and sprinkle with 3/4 teaspoon salt and 1/2 teaspoon pepper. Heat vegetable oil in a 12-inch ovenproof heavy skillet over medium-high heat until it shimmers, then brown pork on all sides, about 6 minutes total.

   Step 3

   Transfer pork in skillet to oven and roast until an instant-read thermometer inserted into center registers 145 to 150°F, 20 to 25 minutes. Transfer to a cutting board and let stand 10 minutes.

   Step 4

   While pork stands, add vinegar to skillet (be careful; handle will be very hot) and boil, scraping up any brown bits, until slightly reduced, about 30 seconds. Transfer to a heatproof measuring cup and add enough olive oil to bring total to 3/4 cup liquid.

   Step 5

   Pulse 3/4 cup walnuts with garlic, water, 1/2 teaspoon salt, and 1/4 teaspoon pepper to a coarse paste in a food processor. With motor running, slowly add oil mixture to make vinaigrette.

   Step 6

   Toss arugula and endive with just enough vinaigrette to coat, then divide among plates. Top with thin slices of pork and drizzle with remaining vinaigrette. Crumble remaining 1/4 cup walnuts over pork.