Place steaks in a shallow dish just large enough to hold them snugly or in a large plastic bag. In a small bowl, stir 3 tablespoons chili-garlic sauce with fish sauce, sesame oil, ginger and garlic. Taste and, if you like it spicy, add 1 more tablespoon chili-garlic sauce. Pour mixture over steaks and massage into surface of each steak. Cover dish with plastic wrap or tightly seal bag with an elastic band, squeezing out as much air as possible. Let stand at room temperature 1 hour or refrigerate overnight.
When ready to cook, preheat oven to 500F. Place steaks on a broiler pan or set on a wire rack over a foil-lined baking sheet. Spoon any excess marinade over steaks. Roast in centre of 500F oven, without turning, until beef gives slight resistance when pressed with your finger, from 10 to 12 minutes for medium-rare for a 1-inch steak or 15 minutes for a 1-1/2-inch steak. To give steaks a caramelized glaze, turn on broiler after they have roasted 10 minutes and broil until sauce starts to bubble and darken, from 3 to 5 more minutes. Serve immediately with wilted spinach with pancetta and red onion and home-made or store-bought duchesse potatoes.
Classic tenderloin: Omit marinade. Lightly brush steaks with olive or vegetable oil, then grind black pepper over both sides. Roast and broil following directions above.