Preheat the oven to 425°F (220°C). In a large bowl, toss the crinkle-cut potatoes with olive oil, minced garlic, salt, and pepper. Spread the fries in a single layer on a baking sheet.

Bake for 25-30 minutes, turning halfway through, until golden and crispy. Remove from the oven and sprinkle with grated Parmesan cheese. Return to the oven for an additional 5 minutes until the cheese is melted. Garnish with chopped parsley before serving.

While the fries are baking, season the sirloin steaks generously with salt and pepper on both sides. In a large skillet, heat 1 tablespoon of butter and 1 tablespoon of olive oil over medium-high heat until hot.

Add the steaks to the skillet and sear for about 4-5 minutes on each side for medium-rare, depending on thickness. In the last minute of cooking, add the remaining butter and rosemary to the skillet. Spoon the melted butter over the steaks as they finish cooking.

Remove the steaks from the skillet and let them rest for 5 minutes before slicing.

In the same skillet, add 1 tablespoon of olive oil and heat over medium heat. Add the chopped onion and sauté until softened, about 3-4 minutes. Stir in the minced garlic and cook for another minute until fragrant.

Add the beef broth and whole black peppercorns, bringing the mixture to a simmer. Stir in the cornstarch mixture and cook until the gravy thickens, about 2-3 minutes. Season with salt to taste.

Slice the rested sirloin steaks and arrange them on plates. Serve alongside the garlic-Parmesan crinkle fries and drizzle with the savory peppercorn gravy.