In a bowl, combine the mashed beans, vital wheat gluten, and seasonings. Mix until small clumps form.
Add ¼ cup vegetable broth, then continue adding small amounts at a time, mixing until the mixture becomes very clumpy.
The dough should not be overly wet — you may need slightly more or less broth.
Knead the mixture with your hands until it comes together into a smooth dough. It should feel spongy, smooth, and bouncy to the touch.
Bring 2 cups vegetable broth and 4 cups water to a boil in a large pot.
Cut the dough ball into 4 equal pieces. Roll each piece very thin into a rectangle. Cut it into 4 equal strips, then cut each strip in half, yielding 8 nuggets per quarter. Shape each piece into a nugget and set aside on a plate. Repeat until all dough is used.
Once the broth is boiling, carefully add the seitan pieces. Boil for 20–30 minutes, stirring occasionally, until the nuggets are chubby and puffed.
While the seitan boils, prepare three bowls: seasoned flour, non-dairy milk, seasoned breadcrumbs (in a wide, shallow dish)
Remove the seitan nuggets and drain well. Place them on a paper towel–lined dish. Let cool for 5 minutes (they will be hot).
Dredge each nugget in flour, dip into non-dairy milk, then coat in breadcrumbs. Set aside until all nuggets are breaded.
Pan Fry + Baking Option: Preheat oven to 450°F (230°C). Heat ½ tbsp olive oil in a pan over medium heat. Fry half the nuggets for 2–3 minutes per side, until golden and crispy. Repeat with remaining nuggets. Transfer to a parchment-lined baking sheet and bake for 20 minutes.
Bake only: Lightly brush nuggets with oil (or skip for oil-free). Bake for 25–30 minutes, flipping halfway through, until golden brown.
Pair with your favorite dipping sauce and enjoy.