Heat oven to 425°F. Line a sheet pan with parchment for easy cleanup.
Toss broccoli with neutral oil, salt, and pepper. Spread in a single layer on the pan.
Roast until edges are browned and crisp-tender, 15–18 minutes. Cool 5 minutes.
Whisk mayonnaise, sweet chili sauce, sriracha, rice vinegar, soy sauce, honey, lime juice, garlic, and sesame oil until smooth.
Combine cabbage, carrots, green onions, cilantro, and peanuts in a large bowl.
Fold in roasted broccoli. Add dressing a bit at a time and toss to coat.
Taste and adjust salt, heat, or acidity. Sprinkle with sesame seeds and extra peanuts to serve.