Place the sliced steak, 2 tablespoons reduced sodium Tamari, and 1 tablespoon Bob’s Red Mill Gluten-Free Sweet Rice Flour in a large zip-top bag. Seal the bag and massage it to evenly coat the steak. Refrigerate to marinate for 20 minutes.

While the steak marinates, whisk together the remaining 1/2 cup reduced sodium Tamari, the remaining 1-1/2 tablespoons Sweet Rice Flour, 3/4 cup gluten-free chicken broth, 1/4 cup brown sugar, 1 tablespoon rice vinegar, 1 teaspoon sesame oil, 3 cloves minced garlic, 1/2 teaspoon ground ginger, and 1/2 teaspoon red chili pepper flakes in a bowl. Set this sauce mixture aside.

Heat a large wok or nonstick skillet over high heat until very hot. Add 1/4 cup water and the 4 cups broccoli florets. Stir-fry, tossing frequently, until the broccoli is bright green and crisp-tender, about 2–3 minutes. Transfer the broccoli to a plate and set aside.

In the same hot wok/skillet (no additional water needed), add the sliced red bell pepper and stir-fry until crisp-tender, about 2–3 minutes. Transfer the bell pepper to the plate with the broccoli and set aside.

Wipe the wok/skillet if there is excess water, then heat 1 tablespoon grapeseed or vegetable oil over high heat. Remove half of the marinated beef from the bag, shaking off excess marinade, and spread it in a single layer in the pan. Let the beef sit undisturbed until seared, about 30 seconds, then stir-fry briefly until it is just barely cooked through (a little pink is okay). Transfer the cooked beef to the plate with the vegetables.

Add the remaining 1 tablespoon oil to the pan and cook the remaining beef the same way: spread in one layer, sear about 30 seconds, then stir-fry until just barely cooked through. Transfer this beef to the plate with the first batch.

Pour the reserved sauce mixture into the hot wok/skillet. Bring it to a simmer and cook, stirring, until it is slightly thickened, about 2–3 minutes.

Return the cooked broccoli, red bell pepper, and beef to the wok/skillet with the sauce. Stir everything together until evenly coated and heated through, 1–2 minutes.

Serve the beef and broccoli over cooked rice and garnish with sesame seeds and chopped green onion.