Batter: whisk everything until smooth and let rest 20–30 minutes.
Cook protein first: season shrimp and pork with salt & pepper, sear pork until lightly golden then remove, sear shrimp until just cooked then remove.
Start the bánh xèo: heat a nonstick pan on medium-high, add 1–2 tbsp oil, pour a thin layer of batter and swirl to spread, then immediately lower heat to medium.
Build + Steam: add the pork, shrimp, and bean sprouts to one half of the bánh xèo, cover with a lid and steam for 2 minutes.
Crisp: uncover, pour 2 tbsp oil around the edges, tilt and swirl so oil runs underneath, cook until edges are golden and lacy and the bottom is deeply crispy, then fold in half.
Repeat: for each bánh xèo start on medium-high heat, pour batter, then drop to medium heat.
