In a small mixing bowl whisk together the beef stock, soy sauce, brown sugar,ginger and red pepper flakes until combined and set aside.
Cut your chuck roast into thin slices and place them into the slow cooker.
Pour in the sauce, add the minced garlic and mix.
Cook on low for 6-8 hours or high for 3-4 hours.
In a small bowl mix the cornstarch and 1/2 cup of the sauce or water until you have a slurry. Pour it into the beef and broccoli and stir. Turn up the heat to high if it's set to low, let cook for 30 minutes to thicken.
Then Add in the broccoli for 20-30 minutes and let it cook through.
Serve over mashed potatoes, white rice, or pasta.
Video
Notes
Other cuts of beef that work in this recipe are skirt steak, flank steak, top sirloin, or hanger steak.Adding the broccoli in the last 30 minutes is perfect for a slightly firmer broccoli texture. If you prefer softer broccoli you can add it earlier but not at the beginning or else it will just be mush.