Crumble the tempeh into small pieces (aim for thumbnail size) and place it in a medium pot.
Cover the tempeh with vegetable broth and soy sauce.
Over medium heat, simmer the tempeh for 20 minutes. Use this time to prep the rest of the ingredients.
Drain the tempeh crumbles over a colander or mesh strainer. Use the back of a spoon to press the moisture from the tempeh.
When the tempeh is done, drain it being sure to press it down a bit to get as much moisture out as possible.
Preheat the oven to 425 F (220 C).
Add the tempeh and all the ingredients except vital wheat gluten to a food processor. Pulse a few times to mix the ingredients. Leave a little texture rather than blending it smoothly.
Transfer the burger mixture into a medium bowl and add ½ a cup of vital wheat gluten. Use your hands to knead in more vital wheat gluten until you can form a ball or patty that will hold together.
Make 4 burger patties (or 6 small patties), about ½ inches thick, and place them on a parchment-lined baking tray.
Bake for 15-20 minutes until firm in the middle and slightly brown. Flip and bake for another 10-15 minutes.
Bake for 15 minutes, flip, and bake another 10 – 15 minutes more until the burgers are slightly brown on the top and are firm, but not hard.
Air Fry. Preheat the air fryer to 375 F. Place the patties in a single layer in the air fryer basket. Fry for 11 to 13 minutes, flipping the burgers halfway through.
Pan Fry. Heat a large skillet or frying pan to medium heat. Add the burger patties and cover them for the first 5 minutes or so to help the middle cook. Flip the burgers and cook until both sides are brown and the middles are firm.