Cube the steak into 1-inch bite-sized cubes and place them in a bowl. Sprinkle with baking soda. This will help tenderize the beef.
Whisk together the marinade ingredients and set aside ⅓ cup for glaze.
Pour the rest of the marinade to mix with the steak and marinate for at least 1 hour and upto 6 hours in the fridge. If you use bamboo or wooden skewers, now is a good time to soak them in water.
Prep the vegetables. Break larger chunks of broccoli florets to bite sizes and cut the vegetables into the same size chunks as the beef.
Assemble the kabobs. Thread the marinated beef on the skewers, alternating with vegetables. Aim for about 4 -5 pieces of beef per 10-inch skewer. Try not to pack them too tight. I like to keep 3 layers of onion together in each chunk so it doesn’t get burnt easily.
Preheat the grill to high heat then reduce to medium-high. Lightly brush the grill gates with oil. Grill the kabobs for 8-10 minutes, turning every 2-3 minutes and brush with more glaze every time you turn the skewers until the steak is cooked to medium-rare/medium and the vegetables are slightly charred.
Transfer the kabobs to a large serving platter. Sprinkle with sesame seeds, if using. Serve warm.
For the beef kabob marinade, if you use tamari, add a bit of sweetener such as regular honey or keto honey or coconut palm sugar to the marinade to balance the salty flavor.