Run the pork pieces through a meat grinder, or have your butcher do this. If this isn't an option, you can skip this step.
2½ lbs pork tenderloin
Place the pork in a large food processor and add the fish sauce, salt, sugar, pepper, garlic, powder, and onion powder. Pulse until fully incorporated.
2 tbsp fish sauce, 1 tsp Kosher salt, 1 tbsp sugar, 1 tsp white pepper, 1 tsp garlic powder, 1 tsp onion powder
Warm the water in the microwave. Whisk in the cream of tartar, baking soda, and potato starch.
⅔ cup warm water, 2 tsp cream of tartar, 1 tsp baking soda, 1 tbsp potato starch
Pour the wet mixture into the meat mixture, and process for 20 to 30 seconds.
Place the meat mixture in a medium bowl, cover, and place in the freezer for 2 hours, or in the refrigerator overnight.
Remove from the freezer (or refrigerator) and divide into two loaves.
Wrap each loaf tightly with several layers of banana leaves. Or, wrap tightly with plastic wrap (Saran Wrap works well). Secure all over with kitchen twine. See video and blog post photos for visual guidance.
1 package banana leaves
Steam the loaves for 45 minutes. Turn off the heat and keep the cha lua in the steamer for 60 to 90 minutes.
Remove the string and plastic wrap and slice.