Season Steak: Place the steak on a wire rack set inside a rimmed baking sheet. Season all sides with 1½ teaspoons kosher salt and ¾ teaspoon black pepper.
Roast Steak: Preheat the oven to 250°F. Roast the steak for 35 to 45 minutes, or until the center reaches 120°F on an instant-read thermometer.
Cook Bacon: While the steak roasts, place the diced bacon in a large skillet over medium heat. Cook for 8 to 10 minutes, stirring occasionally, until browned and crisp.
Reserve Bacon and Fat: Transfer the cooked bacon to a heatproof bowl using a slotted spoon. Carefully pour off any excess bacon fat, leaving about ¼ cup in the skillet.
Sear Steak: When the steak reaches 120°F, remove it from the oven. Heat the bacon fat over medium-high heat and sear the steak for 1 to 2 minutes on each broad side.
Sear Edges: Hold the steak with tongs and sear the edges and fat cap for 30 to 60 seconds per section. The center should reach about 125°F to 130°F for medium-rare before resting.
Rest Steak: Transfer the steak to a clean cutting board. Let it rest for 10 minutes while you prepare the sauce and salad.
Cook Shallots: Reduce the skillet heat to medium. Add the chopped shallots and cook for about 2 minutes, stirring frequently, until softened.
Cook Flour: Sprinkle the flour over the shallots and bacon fat. Stir continuously for about 1 minute, making sure no dry flour remains.
Make Pan Sauce: Slowly pour in the beef stock while stirring and scraping the browned bits from the bottom of the skillet. Simmer over medium heat for 4 to 5 minutes, stirring occasionally, until smooth and thickened.
Add Bacon: Return the cooked bacon to the skillet. Stir and simmer for 1 to 2 minutes, then reduce the heat to low to keep the sauce warm.
Combine Salad: Place the halved tomatoes, Kalamata olives, chopped basil, and shaved Parmesan in a large mixing bowl.
Dress Salad: Drizzle the olive oil over the salad. Add the remaining ½ teaspoon kosher salt and ¼ teaspoon black pepper.
Toss Salad: Gently toss until the tomatoes, olives, basil, and Parmesan are evenly coated with the oil and seasonings.
Slice Steak: After the steak has rested, slice it against the grain into thick slices. Its final temperature should be about 130°F to 135°F for medium-rare.
Serve: Arrange the sliced steak on a serving platter or individual plates. Spoon the warm bacon pan sauce over the steak and serve with the tomato-olive salad.