Set beef out at room temperature 1 hour prior to cooking. Heat oven to 300F (148C). Line a rimmed baking pan with a roasting rack.
Heat a large cast iron or stainless pan over medium-high heat. Rub tenderloin with 2 teaspoons (10ml) of canola oil and season salt and pepper. Sear beef on all sides until well browned, about 5 to 7 minutes. Remove tenderloin from pan and reduce heat to medium.
Add butter and shallot to pan and cook until softened, about 2 to 3 minutes. Add garlic and cook for 2 minutes. Add wine and cook down until mostly evaporated. Stir in horseradish, parsley and rosemary. Season with salt and pepper. Transfer to a small bowl to cool slightly.
Lay out two pieces of prosciutto on a large cutting board so two short ends overlap by one inch to create a 15-inch (38 cm) strip. Lay two more strips down overlapping long edge by ¼-inch (1/2 cm). Repeat with remaining strips to create a 15x10-inch (38x25cm) surface. Spread prosciutto with shallot mixture to within 1/2-inch (1cm) of edges. Place tenderloin on top and roll the tenderloin in prosciutto tucking edges under to seal. Transfer it onto the rack-lined pan. Nestle rosemary sprigs around roast and drizzle with canola oil. Season with pepper.
Roast in oven until the internal temperature reaches 130F (55C), about 50 to 60 minutes. Cover with aluminum foil and rest for 20 minutes before serving.