Roasted Beef Chuck with Horseradish-Parsley Sauce

FOR THE BEEF: Pull roast into 2 pieces at major seam delineated by line of white fat, cutting with boning knife as needed. Using knife, remove large knobs of fat from each piece.

Sprinkle roast pieces all over with salt and pepper. Place pieces back together along major seam. Tie together with kitchen twine at 1-inch intervals to create 1 evenly shaped roast. Wrap tightly in plastic wrap and refrigerate for 18 to 24 hours.

Adjust oven rack to lower-middle position and heat oven to 275 degrees. Set wire rack in rimmed baking sheet. Unwrap roast and rub all over with oil. Place roast on prepared wire rack. Transfer sheet to oven and roast until meat registers 145 to 150 degrees, 3¼ to 3¾ hours. Transfer roast to carving board, tent with aluminum foil, and let rest for 45 minutes.

FOR THE SAUCE: Meanwhile, pulse parsley, horseradish, shallot, capers, lemon juice, garlic, and salt in food processor until parsley is finely chopped, 6 to 8 pulses, scraping down sides of bowl as needed. Transfer to bowl and stir in oil until combined. Season with salt to taste; set aside.

Slice roast thin, removing twine as you go so roast stays intact. Serve, passing sauce separately.