1 1/2 pounds rib-eye steak (about 1/2 inch thick)
3 tablespoons light brown sugar
2 tablespoons ground coriander
1 tablespoon ground turmeric
1 1/2 teaspoons ground cumin
1 1/2 teaspoons freshly ground pepper
3 tablespoons Asian fish sauce or soy sauce
3 tablespoons vegetable oil
3 tablespoons vegetable oil Singapore Cucumber Relish (optional, recipe follows), for serving Fried Garlic Peanut Sauce (optional, recipe follows), for serving

Cut the steak, including the fat, into 1/2-inch cubes and place in a nonreactive mixing bowl. Stir in the brown sugar, coriander, turmeric, cumin, pepper, fish sauce and oil. Let the beef marinate in the refrigerator, covered, for at least 2 hours. Drain the cubes, discarding the marinade. Thread the beef onto bamboo skewers, leaving the bottom half of each skewer bare for a handle and 1/4-inch exposed at the pointed end. Refrigerate, covered, until ready to grill. Heat the grill to high. Brush and oil the grill grate. Arrange the sates on the hot grate, with the aluminum foil shield under the exposed ends of the skewers to keep them from burning. Grill until cooked to taste, 1 to 2 minutes per side for medium rare.

Singapore Cucumber Relish

2 Kirby (pickling) cucumbers, or 1 medium-size cucumber, cut in half lengthwise and seeded
1 shallot, minced (2 to 3 tablespoons), or 1 scallion, both white and green parts, trimmed and minced 1 small hot red chile, such as a bird or cayenne pepper, stemmed, seeded, and minced
2 tablespoons rice vinegar
1 tablespoon sugar Coarse salt (kosher or sea) and freshly ground black pepper

Cut the cucumber(s) into 1/4-inch dice. Place the cucumber(s), shallot, chile, rice vinegar, and sugar in a mixing bowl and toss gently to mix. Season with salt and pepper to taste. The relish can be made up to 2 hours ahead.
Fried Garlic Peanut Sauce

2 tablespoons vegetable oil
5 cloves garlic, 3 cloves thinly sliced crosswise and 2 cloves minced
1 shallot, minced
1 stalk lemongrass, trimmed and minced, or 2 strips (each 1/2 by 2 inches) lemon zest
1 to 3 small hot chiles, such as Thai chiles or serrano or jalapeno peppers, stemmed, seeded, and minced (for a hotter peanut sauce, leave the seeds in)
1 tablespoon dried shrimp, minced, or 1 teaspoon fish sauce (optional)
3/4 cup peanut butter
1 cup unsweetened coconut milk, or as needed
2 tablespoons sugar, or more to taste
2 tablespoons soy sauce
1 teaspoon fresh lime juice, or more to taste
1 tablespoon finely chopped cilantro Coarse salt (kosher or sea) and freshly ground pepper

Heat the oil in a wok or saucepan over medium-high heat. Add the sliced garlic and cook, stirring, until golden, 2 minutes. Remove the garlic with a slotted spoon to paper towels to drain. Add the 2 cloves of minced garlic, the shallot, lemongrass, chile(s), and dried shrimp, if using, to the wok and cook over medium-high heat until fragrant and lightly browned, 2 minutes. Stir in the peanut butter, coconut milk, sugar, soy sauce, fish sauce, if using (instead of the dried shrimp), lime juice, and 3/4 cup water. Reduce the heat and gently simmer the sauce until it is thick but pourable, 5 to 8 minutes. Stir in the cilantro during the last 2 minutes of cooking. Just before serving, stir in the fried garlic slices. If the sauce has gotten too thick and pasty, add a tablespoon or so of water. Taste and correct the seasoning, adding salt and pepper, and more sugar and lime juice if needed. The sauce should be richly flavored.