Preheat your oven to 425°F (220°C). Rinse the cut potatoes in cold water to remove excess starch, then pat them dry with a paper towel.

Toss the shoestring fries in a large bowl with olive oil, chopped rosemary, salt, and pepper. Spread the fries in a single layer on a baking sheet and bake for 25-30 minutes, flipping halfway through, until golden and crispy.

While the fries are baking, season both sides of the filet mignon steaks with salt and black pepper. In a large skillet, melt 2 tablespoons of butter over medium-high heat. Add the crushed garlic and rosemary sprigs, cooking for about 1 minute until fragrant.

Add the filet mignon to the skillet and sear for 4-5 minutes on each side for medium-rare, basting the steaks with the garlic-infused butter throughout the cooking process. Remove the steaks from the skillet and let them rest for 5 minutes.

In the same skillet, reduce heat to medium and add the heavy cream, scraping up any browned bits from the bottom of the pan. Stir in Dijon mustard, Worcestershire sauce, and chopped parsley. Simmer for 3-5 minutes until the gravy thickens slightly. Season with salt and pepper to taste.

Plate the garlic-basted filet mignon alongside the rosemary-salted shoestring fries. Drizzle the creamy herb gravy over the steaks and serve immediately.