Marinate the steaks for at least 30 minutes in 4 tbsp sunflower oil, the red chili and the vinegar. Turn regularly.
Pour some sunflower oil in a non-stick pan and place it over high heat until hot. Then sear the marinated steaks for 4 minutes on all sides (or cook them the way you like). Season with salt to taste. Add the remaining marinade at the very last minute.
Then put the cooked steaks onto a plate. Cover with tinfoil and let them rest for a couple of minutes.
Add the shallots to the hot pan and let the anchovy fillets melt into the sauce over medium heat. Stir well.
Place the steaks onto hot plates, drizzle with the spicy sauce and finish with shredded basil and a sprinkle of salt to taste.