3 tablespoons palm or brown sugar, or more to taste
3 to 4 tablespoons fish sauce, or more to taste
2 to 3 tablespoons fresh lime juice, or more to taste
Two 1-inch-thick hanger steaks (about 7 ounces each), center chain removed
Sea salt and freshly ground black pepper
1 tablespoon canola or grapeseed oil
2 tablespoons Chinese rice wine (Shaoxing) or dry sherry, or more to taste
4 garlic cloves, thinly sliced
1½ inches fresh ginger, peeled (use the edge of a teaspoon to scrape off the skin) and thinly sliced crosswise
6 fresh Thai bird chiles (or 3 small jalapeños), thinly sliced crosswise
2 fresh long red or green chiles, such as Anaheim or Hungarian Wax, thinly sliced crosswise
1 medium red onion, halved lengthwise and thinly sliced
½ cup Thai basil leaves (or ⅓ cup fresh mint leaves and 2 tablespoons small basil leaves)
½ cup fresh cilantro leaves
1. In a small bowl, stir together the palm sugar, fish sauce and lime juice. Taste and adjust with more sugar, fish sauce or lime juice to make it sweeter, saltier or tangier, as desired. Set aside.
2. Generously season both sides of each steak with salt and pepper. Heat a large cast-iron skillet over medium-high heat until it's smoking, about 2 minutes. Add just enough oil to coat the bottom of the pan, then add the steaks. Cook until browned, about 10 minutes, then flip and cook on the other side until medium-rare, about 6 minutes more. Transfer to a cutting board and let rest for 10 minutes.
3. Remove the pan from the heat (leave the burner on), add the rice wine and use a wooden spoon to stir and scrape up the browned bits from the bottom of the pan. Add the garlic, ginger and chiles, return the pan to the burner and cook until fragrant, about 30 seconds. Turn off the heat and set the pan aside.
4. Slice the rested steak crosswise (against the grain) into thin strips. In a medium bowl, toss the steak with the pan sauce and reserved palm-sugar-lime mixture. Add the onion, basil and cilantro, toss, divide between two plates and serve.