Boil the 6 c vegetable broth with the 3 T soy sauce. Turn off heat and keep covered.
Combine the 1/2 c cold vegetable broth, the 1/4 c soy sauce, olive oil, garlic and lemon zest. Mix.
Add to wheat gluten and mix until wet ingredients are absorbed. Use your hands to knead for about 3 minutes, until dough is elastic.
Divide into 6 equal pieces; stretch each into an oblong cutlet shape that is less than 1/2" thick. Use your body weight to press and shape it on a hard surface; there will be some resistance but just keep at it.
Pour the heated vegetable broth into a 9x13" glass baking dish or ceramic casserole. Place the cutlets in the broth, then bake for about 30 minutes uncovered, turn the cutlets over with tongs, and bake for an additional 20 minutes.
Remove from the oven and place the cutlets in a colander to drain. The cutlets are now ready to use in whatever seitan recipe you choose.
If you have extra seitan, store it in the cooking liquid in a tightly covered container.