Sweat the finely chopped shallot in a small amount of oil in a saucepan until translucent. Stir in the tomato paste and roast for 1 minute. Deglaze with the red wine and simmer vigorously until strongly reduced. Add the beef stock and Worcestershire sauce, then let it simmer gently for 10 to 15 minutes until velvety and glossy. Strain through a fine mesh sieve, whisk in the cold butter until emulsified, and season to taste with salt and pepper. Keep warm on low heat.
Warm the bechamel and vegetable broth together in a separate saucepan over gentle medium low heat. Gradually whisk in the grated cheese in batches until completely melted and smooth. Season with freshly ground black pepper and salt to taste. Keep warm over low heat without letting it boil so the sauce remains creamy and does not separate.
Bring a large pot of salted water to a rolling boil and cook the fettuccine until al dente according to package directions. Just before draining, scoop out approximately 100 ml of starchy pasta water. Drain the fettuccine and transfer it immediately into the warm cheese sauce, tossing gently for 1 to 2 minutes while adding a splash of pasta water as needed to achieve a glossy coating.
Pat the tenderloin steaks completely dry with paper towels and season generously on all sides with salt and freshly ground black pepper. Heat a heavy skillet until smoking hot. Sear the steaks for 2 to 3 minutes per side for medium rare. Add the butter to the skillet during the final minute and baste the foaming butter continuously over the meat. Transfer the steaks to a warm board and let them rest for 5 minutes (target core temperature 52 to 54°C).
Twirl a portion of the creamy cheese fettuccine onto each warmed plate. Place a rested beef tenderloin steak alongside, spoon the glossy Roti sauce generously around and over the meat, and finish with a lavish sprinkle of coarsely cracked black pepper. Serve immediately while piping hot.