Roast Beef Tenderloin with Horseradish Cream

Name: Roast Beef Tenderloin with Horseradish Cream
Ingredients: 1 /2 cup plus 2 tablespoons crème fraîche or sour cream (about 5 ounces); 1 1/2 tablespoons (or more) drained prepared horseradish; 1 1/2 tablespoons drained green peppercorns, minced, or coarsely ground pink peppercorns; Kosher salt; 3 garlic cloves, chopped; 1 tablespoon chopped fresh thyme; 2 1/2 teaspoons kosher salt; 1 1/2 teaspoons freshly ground black pepper; 1 1/2 teaspoons freshly ground pink peppercorns; 1 3-pound center-cut beef tenderloin at room temperature; 1 bunch fresh rosemary; 1 tablespoon olive oil; 1 tablespoon unsalted butter