Whisk together rice flour, cornstarch, coconut milk, water, and turmeric in a bowl until smooth, then let rest for 15 minutes—this hydrates the flour for better texture.

Heat a 10-inch non-stick skillet over medium-high heat (375°F) and add 1/2 tablespoon of vegetable oil.

Sauté pork belly slices for 3–4 minutes until lightly browned, then push to one side of the skillet.

Add onion slices and cook for 1 minute until slightly softened.

Stir the batter briefly and pour about 1/2 cup into the skillet, immediately swirling to coat the bottom thinly.

Scatter bean sprouts over half of the pancake and cover the skillet with a lid for 2 minutes to steam the sprouts.

Uncover and cook for another 3–4 minutes until the edges curl and turn golden brown and crispy.

Fold the pancake in half over the bean sprouts using a spatula, then transfer to a plate.

Repeat steps 2–8 with remaining batter and ingredients, adding oil as needed to prevent sticking.

Serve immediately with fish sauce for dipping.