To a 9” by 13” pan, add the oyster sauce, fish sauce, and brown sugar sweetener.
Add the steaks and thoroughly toss them in the mixture until well coated. Allow the steaks to marinate in the refrigerator for 30 minutes to an hour.
In the meantime, make the dipping sauce. Combine the fish sauce, tamarind puree, brown sugar sweetener, sliced red onions, chopped cilantro, the juice of one whole lime, and the Thai chilies (about 10 small) that have been dried and crushed in a mortar pestle. Stir the mixture and taste, adjust to your liking by adding more fish sauce or sweetener. Finally, add the toasted rice powder (1 tsp). See last step on how to make it from scratch. This will thicken the sauce slightly and add a nice toasted flavor.
Preheat a large nonstick skillet over medium-high heat until hot. Add the avocado oil and swirl the pan to coat. Add two steaks simultaneously, searing on the first side until nicely browned, about 3-4 minutes. Turn the heat down if the marinade on the steaks is starting to burn. Flip the steaks and repeat on the other side. Remove the first two steaks to a plate and repeat with any remaining steaks. This process will not cook the steaks entirely through. Once the second set of steaks are seared, add them all back into a pan and cook them, occasionally flipping until they are medium-rare. Allow the steaks to rest for 5 minutes before slicing into them. Slice them and serve alongside the spicy dipping sauce.
To make the toasted rice powder, toast a small amount of glutinous rice in the air fryer at 350 F for 10-12 minutes until roasted.
Then crush it in a mortar and pestle.