If you're planning on baking the mini quiche, preheat the oven to 350 degrees. If you're air frying, skip this step. (Note that the quiche air fry at a different temperature.)
For easiest blending, I recommend putting the soft or liquid ingredients into the blender pitcher first. Put soaked & drained raw cashews, non-dairy milk, hot sauce, white miso paste, and stoneground mustard into the blender pitcher. Then crumble the super firm tofu into the blender pitcher. Blend until smooth. If you're using a Vitamix blender, press the ingredients with a tamper to get everything fully blended. If not, stop occasionally to scrape down the sides, so that everything gets evenly combined and there are no whole pieces of cashew left.
Now it's time to add the dry ingredients to the blender. Add nutritional yeast flakes, granulated onion, paprika, cumin, ancho chili powder, kala namak, and turmeric. Blend to combine. (If it doesn't get completely incorporated, that's okay. You'll have a chance to mix it more evenly in a second.)
Bring a skillet to a medium heat. Add oil to the skillet along with seitan bacon or sausage. Brown for a couple minutes. Then add red bell pepper, onions, and curly kale. Cook for two or three minutes more, until the kale is softened & bright green. You don't have to worry about getting everything super cooked, because it will cook further in the air fryer or oven.
In a large mixing bowl, combine the tofu mixture from the blender with the seitan bacon & vegetable mixture from the skillet. Make sure everything is evenly incorporated and combined by using a spoon or your your hands. (If you're using your hands, just make sure the vegetable mixture isn't too hot, so that you don't get burned.)
Now it's time to fill the silicone muffin cups. Even if you're air frying the quiche, it can be handy to put the silicone baking cups into a metal muffin pan for easier filling. You will need about 10 baking cups. (My cups didn't require any oil, and popped out just fine without sticking. If you're concerned about yours, lightly oil your baking cups before filling.) Use a ¼ measuring cup to evenly distribute the quiche batter. Use your hands to scoop it from the measuring cup, form a ball, and lightly press it into a baking cup. (The batter will be the texture of a sticky falafel batter.) Continue filling the baking cups until all of the quiche batter has been used. Sprinkle the tops of the mini quiche with paprika for extra color.
TO BAKE THE VEGAN QUICHE: Bake at 350 degrees for 30 minutes.
TO AIR FRY THE VEGAN QUICHE: Put the silicone baking cups into the air fryer. Depending on the size of your air fryer basket, you may have to work in batches. About 6 mini quiche fit into a 3.7 quart sized air fryer. Air fry at 330 degrees for 14 to 16 minutes. Keep in mind that the second batch will likely cook a little faster, because the air fryer will already be hot.
To see if the quiche is ready, put a toothpick into the center of one. If it comes out clean, it's ready. Keep in mind that the quiche will continue to get firmer as it cools, especially upon refrigeration. Once the quiche is done, remove from muffin cups and serve right away, or refrigerate for later. They're great hot, cold, or at room temperature.