My Family's Favourite Roasted Whole Beef Sirloin

Ingredients

• 1 whole beef sirloin (approximately 3-4 kg or 6-8 lbs)
• Salt and freshly ground black pepper to taste
• 2 tablespoons unsalted butter, softened (28 g)
• 2 tablespoons olive oil (30 mL)
• 4 garlic cloves, minced
• 2 cups fresh parsley, finely chopped (60 g)
• 2 tablespoons fresh rosemary, finely chopped (30 g)
• 2 tablespoons fresh thyme, finely chopped (30 g)
• Zest of 1 lemon
• ½ teaspoon red pepper flakes (optional)