Preheat oven to 400°F. Toss 8 cups broccoli, 2 tablespoons oil and ¼ teaspoon each salt and pepper in a 9-by-13-inch metal baking pan (do not use a glass pan, which could shatter). Roast, stirring once, until browned in spots and slightly tender, 15 to 20 minutes.,

Whisk ⅓ cup broth, 1 tablespoon miso, grated garlic and ½ teaspoon ginger together in a small bowl. Stir the broth mixture into the pan with the broccoli. Roast until the liquid is almost completely reduced, 5 to 10 minutes.,

In a small bowl, stir 1 teaspoon rice vinegar and ¾ teaspoon chili crisp together; drizzle over the broccoli. Sprinkle with ¼ cup scallions. Garnish with sesame seeds, if desired.