Grilled Yu Choy

Bring garlic, shallots, ginger, salt, and 2 cups oil to a simmer in a medium saucepan over medium heat. Reduce heat to low and simmer gently until aromatics are softened, 8–10 minutes. Add red pepper flakes and cook, adjusting heat as needed to maintain a bare simmer and stirring occasionally, until oil is very deep red and aromatics are very lightly browned, 45–60 minutes.

Meanwhile, grind mushrooms, if using, in spice mill or with mortar and pestle to a powder.

Remove sate oil from heat; stir in sugar, mushroom powder, and remaining ½ cup oil (this will help cool it down). Let cool slightly before using.

Do Ahead: Sate oil can be made 2 months ahead. Transfer to an airtight container; cover and chill.

Prepare a grill for medium-high heat; oil grate. Place yu choy on a rimmed baking sheet. Drizzle with vegetable oil, season with salt, and toss to coat. Grill, turning occasionally, until lightly browned and crisp-tender, about 4 minutes. Transfer to a platter; drizzle with sate oil, including the crispy bits.