In a small mixing bowl mix together the soy sauce, brown sugar, green onion, garlic and sesame oil until the sugar has dissolved. Place the top sirloin into a large zip top bag and add the marinade. Seal and mix, then chill for at least 4 hours or overnight.
To prepare: In a large skillet add a few drizzles of olive oil with the sesame oil over high heat.
Add the broccoli florets, green onion, minced garlic, ginger and water. Saute over high heat for 2 minutes or until the broccoli is crisp tender and bright green. Season lightly with salt and red pepper flakes. Remove to a platter.
Heat a couple of drizzles of olive oil in the same skillet. Remove the steak strips from the marinade. Discard the marinade.
Lay the steak strips flat in the pan. Cook over high heat, allowing the meat to brown and the drippings to reduce, about 4-5 minutes.
Add the broccoli back to the pan and drizzle with 1/4 cup hoison sauce. Saute just until heated through and the sauce is evenly distributed. Remove from the heat. Sprinkle with toasted sesame seeds
Serve immediately over hot rice.