In a large bowl, whisk together the soy sauce, sesame oil, sherry, erythritol, and cornstarch until everything has dissolved into the liquid.
Add the sliced beef and toss to evenly coat in the marinade.
Allow beef to marinate in the fridge for 30 minutes.
Heat veggie oil in a wok or large skillet over medium-high heat.
Once shimmering, add ginger and garlic. Stir constantly (garlic can easily burn at this temp), and cook until fragrant - about 1-2 minutes. Use a slotted spoon to carefully remove ginger and garlic from the oil, and discard.
Add the broccoli. Cook in the oil until bright green (about 5-7 minutes). Use a slotted spoon to place broccoli on a clean plate, and set aside.
Add the beef and marinade to the skillet.
Cook the beef in the marinade until it is no longer pink.
Add the broccoli back to the wok/skillet and toss together for 3-5 minutes -- you'll know it's done once the broccoli has heated through.
Optional (I always do this because I prefer a thicker sauce, especially since low carb "rice" doesn't soak up sauce as well as traditional): remove the beef and broccoli to a clean plate using a slotted spoon, leaving the sauce in the pan. Heat the sauce to a heavy simmer, and continue to reduce until it has thickened to your liking. Pour over the beef and broccoli and toss everything together.
Serve over cauliflower rice, and top with sesame seeds and sliced green onions. Enjoy!