Prep. Preheat the oven to 425˚F. Grease a rimmed baking sheet with cooking spray and set aside.
Make the sesame sauce. In a large bowl, combine the soy sauce, sesame seed oil, brown sugar, olive oil, vinegar, granulated sugar, and salt; whisk until thoroughly incorporated.
Toss and roast the broccoli. Add the broccoli to the sesame sauce; toss to coat and transfer the broccoli to the prepared baking sheet. Roast them in the oven for 10 minutes.
Toss and roast the steak. Then add the steak to the sesame sauce, toss to coat. Pull out the baking sheet from the oven and arrange the steak bites around the broccoli. Roast for 10 more minutes, or until the steak is cooked through and broccoli is fork tender.
Serve. Remove from the oven and transfer the broccoli beef to a serving plate. Serve over prepared rice, garnished with sesame seeds and green onion.