In a large bowl, combine the sirloin tips with olive oil, salt, black pepper, and garlic powder. Mix well to coat the meat evenly.

In a large skillet over medium-high heat, add the seasoned sirloin tips. Sear for about 3-4 minutes on each side, or until browned. Remove the tips from the skillet and set aside.

In the same skillet, reduce the heat to medium. Add the butter and let it melt. Stir in the roasted garlic and cook for 1-2 minutes until fragrant.

Pour in the heavy cream and beef broth, stirring to combine. Add the Dijon mustard and Worcestershire sauce. Bring to a simmer.

Stir in the crushed peppercorns and let the sauce simmer for about 5 minutes, allowing it to thicken slightly.

Return the seared sirloin tips to the skillet, coating them well with the creamy sauce. Simmer for an additional 5 minutes until the meat is heated through.

Sprinkle in the grated Parmesan cheese, stirring until melted and smooth.

Garnish with chopped fresh parsley and serve over mashed potatoes, rice, or pasta.