In a bowl or large liquid measuring cup, whisk together the rice flour, flour, cornstarch, turmeric, and salt. Stir in the can of coconut milk, and 3 cups of water, mixing well. If you have the time, let the batter sit, covered, in the fridge for 1 hour or up to overnight.
When ready to cook, whisk the batter and stir in the sliced green onions.
Heat a small non-stick pan over medium heat. Add a touch of oil and when hot, add some sliced onions, a couple of slices of pork belly and 2-3 shrimp. Cook, unmoving, until the shrimp is pink and the pork belly is seared on one side. Flip all the pieces of pork belly and shrimp.
Stir the bánh xèo batter and spoon or ladle in a small amount of batter into the pan. Swirl to coat. You want just enough batter to thinly coat the bottom of the pan. If needed, spoon in extra batter into any bare spots.
Cook, on medium-low to low heat until the bánh xèo batter starts to crisp up and brown along the edges. It will start to release and curl up a bit.
Take a peek underneath and if it’s brown and crispy, carefully fold in half and remove from the pan. Eat immediately or keep warm in the oven on a wire rack so the bánh xèo doesn’t get soggy.
Repeat making bánh xèo as needed and enjoy the bánh xèo hot with lettuce, fresh herbs, and Vietnamese dipping fish sauce.