To make the Mongolian sauce, whisk together the tamari, broth, and coconut sugar in a small bowl. Set aside.
In a small saucepan, add 1 tablespoon oil, garlic, and grated ginger. Stir fry until fragrant, about 2 to 3 minutes. Add the tamari mixture to the saucepan, bring to a boil, then reduce heat and simmer on low until thickened, about 10 minutes.
For the bowls, toss the beef in 1 teaspoon of oil and then 1 teaspoon of cornstarch. Place in a bowl or Ziploc bag with the Mongolian sauce and marinate in the fridge for 10 minutes or up to 1 hour.
Once marinated, remove the beef from the marinade to a clean bowl and lightly coat the beef strips in an extra 1/4 cup (45 g) cornstarch.
Heat a large skillet with 2 tablespoons (30 ml) of oil, then place the beef strips in the pan. Stand back to avoid the splatters, and use a splatter screen if you have one. Fry in the oil for about 1 minute on each side, browning each steak strip. Set the beef strips on a paper-towel-lined plate and drain the oil from the pan.
Place the beef strips back in the pan with the Mongolian sauce. Reduce the heat, and then cook the meat for 1 minute, stirring to coat. Remove from the heat and set aside.
Cut the broccoli head into 3 or 4 parts. Working in batches, process in a blender or food processor until a riced texture is achieved. Place in a large microwave-safe bowl. Add 1 tablespoon broth, and salt and pepper to taste. Lightly steam in the microwave for 45 seconds to 1 minute.
Divide the broccoli rice among each of the bowls. Add the beef to each bowl and drizzle the sauce on top. Top with the green onions and red pepper flakes. Garnish with the sesame seeds and cilantro.
For an extra-spicy bowl, add 1 sliced red Thai pepper to your sauce or to the beef when frying.
*The sauce also works great with coconut palm sugar or raw turbinado sugar. Honey will work in place of coconut sugar, but the beef will be stickier.
**TO MAKE PALEO: Use cornstarch.
TO STORE: Refrigerate leftovers in an airtight storage container for up to 3 days.
TO REHEAT: Gently rewarm beef and broccoli in a skillet on the stovetop over medium-low heat or in the microwave.
TO FREEZE: Freeze leftovers in an airtight freezer-safe storage container for up to 3 months. Let thaw overnight in the refrigerator before reheating.