In a large bowl, empty the contents of the Banh xeo mix, including the turmeric pouch.
To the bowl, add in the salt, extra turmeric, coconut milk, water, and beer. Whisk to combine until the batter is nice and smooth. Let batter rest for 10-15 minutes. *Optional: you can add in sliced scallions into the batter if you wish at this point.
In a large nonstick pan, heat up about 3-5 tablespoon of oil on medium-high heat. Once heated, scatter some sliced onions if you wish and pour in batter to coat the surface. Swirl the pan to evenly coat the surface. Depending on the type of protein you choose, you can add it before or after you pour the batter. Typically proteins that take longer to cook should go before the batter.
Cover the pan with a lid for 2-3 minutes. Uncover afterwards and add about 1-2 tablespoon of oil along the edges of the pan. Run a rubber spatula under the edges of the banh xeo, so the oil can seep under.
If you choose fast cooking proteins, you may now add them to half of the crepe. Top your protein with a hand full of bean sprouts if you desire as well. Continue to cook for 1 minute, then with a spatula carefully fold the crepe in half and continue to cook until both sides are crispy.
Once the crepe is crispy and your proteins are fully cooked, serve the banh xeo Immediately on a plate with the accompanying vegetables & fish sauce dipping sauce.