Slice the seitan lengthwise in 1 1/2 inches long, pat dry them.
Add on a tablespoon of oil to a frying pan and when hot, add the seitan. Pan sear it until golden brown, approx 7,8 minutes. remove from the pan, add to a plate with pepper towel. Reserve.
On a separate pan, add the vegan butter and the olive oil. When hot, add the onions, the mushrooms, and the salt. In medium heat, saute it for 12 minutes, until everything is golden brown.
Add the crushed garlic, cook for 40 seconds. Add the sweet paprika, stir until combined. Add the wine, stir until alcohol disappears
Add the veggie broth, the miso paste, the thyme, the mustard, the Worcestershire sauce, and the black pepper. let it simmer for 5 minutes.
After 5 minutes, turn off the heat, add the vegan sour cream, the fresh herbs of your choice and serve.