Set oven to 400°F (use convection if available) and line a large baking sheet.
Shred cabbage, remove core, and sprinkle evenly with kosher salt. Massage gently to draw out moisture.
Trim scallions; place whites on cabbage, reserve chopped greens in a bowl for dressing.
In the bowl, add serrano chilies, garlic, lime juice, fish sauce, and 1 tsp salt. Stir in grated carrots; set aside.
Roast cabbage and scallions 10 minutes. Add crumbled tempeh, peanuts, and oil. Toss lightly, roast another 15–20 minutes until golden.
Transfer roasted mix to the bowl with dressing. Toss until well coated.
Spoon over jasmine rice and garnish with cilantro or mint. Serve warm or at room temperature.
