Preheat the oven to 425°F (220°C). Wash and peel the russet potatoes. Using a mandoline slicer or a sharp knife, cut the potatoes into thin, even slices. Arrange the potato slices in a lattice pattern on a baking sheet lined with parchment paper.

Drizzle the olive oil over the potatoes and sprinkle with minced garlic, Parmesan cheese, and salt. Bake in the preheated oven for 30-35 minutes, or until the fries are golden and crispy. Flip halfway through for even cooking.

While the fries are baking, season the filet mignon steaks generously with salt and pepper. In a large skillet over medium-high heat, melt the butter. Add the chopped tarragon and stir for 30 seconds until fragrant.

Add the seasoned steaks to the skillet. Sear for 4-5 minutes on each side for medium-rare, or until desired doneness. Remove from heat and let rest.

In the same skillet used for the steaks, add the olive oil and chopped shallot. Sauté for 1-2 minutes until the shallots are translucent. Stir in the crushed peppercorns and cook for another minute.

Pour in the heavy cream and Dijon mustard, stirring to combine. Bring to a simmer and cook for 3-5 minutes until the sauce thickens. Season with salt to taste.

Slice the filet mignon and place it on a plate. Drizzle with the creamy peppercorn sauce. Serve alongside the garlic-Parmesan lattice fries, garnished with fresh parsley.