In a mixing bowl, add garlic, soy sauce, sesame oil, ground ginger, chinese five spice, apple juice, coconut water, bird's eye chilis and arrowroot flour. Mix until well incorporated and set aside.
Cut the tenderloin into half inch thick slices and cut each slice in half. Add the meat to the reserved marinade you just made; mix to coat, cover and refrigerate for at least an hour (you can also leave this to marinate overnight)
Add a little bit of olive oil to the bottom of a large non-stick pan and preheat over medium-high heat. While the pan is heating, remove the pieces of meat from the marinade and set them on a paper towel to absorb excess liquid. Do NOT discard marinade.
When the pan is hot enough, add the pieces of meat one by one and let them cook until the meat starts to brown, about 2 minutes. Flip the pieces over and continue cooking for another minute or so.
Throw in the onion, bell pepper and broccoli and cook until the vegetables start to soften up and the broccoli is cooked to your liking. Add reserved marinade, continue cooking until the sauce thickens up a bit, about one minute.
Serve garnished with sesame seeds and sliced green onions.