Finely chop the pork and wood ear mushrooms, then sauté until cooked. Add 1 teaspoon salt and 1 teaspoon pepper.

Prepare the agar-agar according to the package instructions. For example, if the instructions say to mix 1 packet with 6 1/3 cups water (1.5 liters), use 5 1/2 cups water (1300 ml) plus 3/4 cup unsweetened milk or coconut milk (200 ml) to give the wrapper a milky white color. Pour a thin layer of the hot agar mixture onto a large round plate. Wait about 1 minute for it to set, then add the filling and roll up the bánh cuốn by hand. (I use two plates—while one sets, I roll the other, so it goes quickly. You can finish in about 15 minutes.)

Store any leftover agar mixture in the fridge to eat later. If you prefer it sweet, you can mix it with sweetened condensed milk for a dessert.