Don’t go for perfect grill marks here. Flip the steaks often so the fat renders evenly without overcooking the meat. And don’t sleep on that herb salad—it brings some freshness to the sticky-salty-sweet steaks.
Step 1
Blend chopped shallots, garlic, ⅓ cup fish sauce, ⅓ cup lime juice, and 2 Tbsp. brown sugar in a blender until smooth.
Step 2
Season steaks lightly with salt (the fish sauce will also season the steaks). Transfer to a large bowl or a 12x9" baking dish. Pour marinade over and turn steaks with tongs to coat evenly. Let sit at room temperature 1 hour, or cover and chill up to 12 hours, turning once (halfway through if you can).
Step 3
Preheat a grill to high heat. Grill steaks, turning every minute or 2, until lightly charred and crisp and an instant-read thermometer inserted into the thickest part registers 140°, 7–9 minutes. Transfer steaks to a cutting board and let rest at least 5 minutes before thinly slicing.
Step 4
Meanwhile, mix chilies, remaining 3 Tbsp. fish sauce, remaining 3 Tbsp. lime juice, remaining 1 Tbsp. brown sugar, and 1 Tbsp. water in a large bowl to combine. Add sliced shallots and herbs and toss to coat; season lightly with salt.
Step 5
Arrange sliced meat on a platter and scatter herb salad over.
