Step 1

Stir together 1 1/2 cups beer and salt in a gallon-size ziplock plastic bag until dissolved. Add steaks to bag, seal, and place on a rimmed baking sheet. Refrigerate 2 hours, turning bag and massaging steaks occasionally.

Step 2

Meanwhile, combine cilantro, lemongrass, and garlic in a blender, and process on high speed until finely minced, about 30 seconds, stopping to scrape down sides as needed. Add oyster sauce, fish sauce, brown sugar, pepper, and remaining 3/4 cup beer, and process on high speed until smooth, about 30 seconds. Remove steaks from refrigerator. Drain and discard beer mixture, and pour cilantro marinade over steaks in bag, massaging gently to coat steaks. Seal bag, and return steaks to refrigerator. Let marinate, turning bag and massaging steaks occasionally, at least 6 hours or up to 12 hours.

Step 3

Heat one chimney of charcoal until flames subside and coals are lightly covered in ash. Arrange coals for two-zone cooking: Bank coals along half of bottom grate of charcoal grill. Add log along edge of coals. Place oiled cooking grate over coals; open bottom and top vents of grill. Cover grill, and heat to medium-high (400°F to 450°F). Remove steaks from plastic bag, and discard marinade. Grill steaks over direct heat, uncovered, flipping often, until caramelized, about 5 minutes. Transfer steaks to indirect heat with fat cap facing coals. Cover and cook, flipping steaks occasionally, until an instant-read thermometer inserted in thickest portion registers 125°F for medium-rare, 30 to 35 minutes. Transfer steaks to a platter, and let rest until internal temperature rises to 135°F, about 10 minutes. Thinly slice against the grain, and serve on rice or with lettuce leaves as wraps, alongside Jeow Som dipping sauce.