For the broth:

7 cups water
2 Tbsp soy sauce
2 sprigs fresh rosemary

For the seitan:
1 1/2 cups vital wheat gluten
1/3 cup nutritional yeast
1 Tbsp tomato paste
1/2 tsp garlic powder
1/4 tsp pepper
1 Tbsp soy sauce
2 Tbsp ketchup
1 Tbsp vegan Worchestershire sauce
1 Tbsp hoisin sauce
2 Tbsp Kitchen Bouquet (optional, for color)

Combine all broth ingredients in a slow cooker.

Combine all the seitan ingredients in a large bowl. Mix until combined and knead intensely for 5 minutes. Ideally, use a mixer with a dough hook or put it in a bread machine on the dough cycle for about 5 minutes.) Let the dough rest 5 minutes.

Stretch the dough out to the thickness you want and cut into desired sizes.

Drop the seitan pieces into the slow cooker. The seitan is done with the pieces float to the top, about 2-3 hours. If you make very large pieces, you will need to turn them over with tongs, and they may not float up.

Refrigerate and/or freeze in broth.