Adjust rack to top position and preheat oven to 425 degrees. Wash and dry produce.

In a small pot, combine rice, 1¼ cups water (2¼ cups for 4 servings), and a pinch of salt. Bring to a boil, then cover and reduce to a low simmer. Cook until rice is tender, 15-18 minutes.

Keep covered off heat until ready to serve.

Cut broccoli into bite-size pieces if necessary. Trim and thinly slice radishes into rounds. Trim and thinly slice scallions, separating whites from greens. Halve pulled mushrooms lengthwise. Halve, peel, and thinly slice onion.

Toss broccoli on a baking sheet with a drizzle of oil, salt, and pepper. Roast on top rack until browned and tender, 15-20 minutes.

In a small bowl, combine vinegar, half the sesame seeds, ½ tsp sugar (1 tsp for 4 servings), and a pinch of salt. Stir in radishes, carrots, and scallion whites. Refrigerate until ready to serve.

Heat a drizzle of oil in a medium pan (large pan for 4 servings) over medium-high heat. Add mushrooms; cook, stirring occasionally, until crisp and warmed through, 3-5 minutes.

Add onion and another drizzle of oil; cook, stirring occasionally, until onion is softened and translucent, 2-3 minutes more.

Reduce heat under pan to medium low and add bulgogi sauce. Stir until mushrooms and onion are evenly coated. Taste and season with salt and pepper. Turn off heat.

Fluff rice with a fork.

Divide rice, mushrooms and onion, broccoli, and pickled veggies between plates in separate sections. Drizzle with as much spicy mayo as you like. Garnish with remaining sesame seeds and scallion greens. Serve.