VARIATION: Vegetarian phở with shredded tofu skin sticks and oyster mushrooms
If you’re using the tofu skin sticks soak them either the night before (or before you leave for work) as they take some time to rehydrate (though I’ve also given a ‘quick’ rehydrate method).
Tofu skin sticks are made from the skin that forms on the surface of simmering soymilk. The skin is gently pulled off, crumpled together and hung on a stick or rack to dry. You can buy dried tofu skin sticks at Vietnamese or Chinese grocers. In Vietnam, you’ll find them at stalls at fresh food markets that sell dried pantry items like dried beans, rice paper wrappers and soy or fish sauce.
2 tofu skin sticks
¼ lb (112 g) oyster mushrooms, torn or cut into bite sized pieces (approximately 2 cups)
To Rehydrate the Tofu Skin Sticks
Long soak method
Eight hours before you plan to eat the soup place the tofu sticks in a casserole dish (snap them, trying to keep them in long lengths, if they’re too long for the dish). Fill the casserole dish with hot tap water. Since the tofu skin sticks will float I’ll use a small mesh rack (you can lay a large stainless steel spoon, or something that won’t float, across them) to keep them immersed. The tofu skin sticks will rehydrate overnight (or put them in the water before leaving for work).
Quick Soak Method
If you’ve forgotten to soak them and need to ‘speed’ up the process, turn your oven on to 200F and add the casserole dish (filled with hot water). (Set the timer on your phone or leave a note near the oven - I sometimes will even tape a piece of paper with the time I should check what's in the oven to the oven door- as a reminder that the tofu skin sticks are in the oven).
I’ve found the constant gentle heat quickens the process of the water penetrating the center of the sticks. They should be ready after about 1 to 1 ½ hours. To fully hydrate the tofu skin sticks they need to be gently hydrated which is why a quick boil, say like boiling pasta, does not work (they lose their shape and become slimy).
The tofu skin sticks are fully hydrated when they have turned a lighter color and when you cut through them there is no dried parts at the core of the stick.
To use them in the soup, cut the sticks into 2-inch (5 cm) lengths and either pull them apart into shreds or cut them 3 or 4 times lengthwise. Discard any parts that are tough (this often tends to be the thin curved part that touched the stick or rack when drying). Place the tofu shreds into a bowl or onto a plate and cover with a damp towel and wrap with plastic wrap so that they don’t dry out.