Heat a large skillet or pan over medium heat. Add a splash of olive oil, then sauté the onion and garlic until softened and translucent.
Add the sliced shiitake mushrooms to the pan, and cook until they're soft and starting to brown, about 5-7 minutes.
Sprinkle the flour over the mushrooms and onions, stirring to coat them evenly. Cook for about 1 minute to remove the raw flour taste.
Gradually pour in the vegetable broth while stirring, to incorporate the flour into the liquid smoothly, avoiding lumps. Add the Pinot Noir (if using) and Dijon mustard, stirring well.
Bring the mixture to a simmer, then add the marinated tofu along with any remaining marinade. Allow the mixture to simmer gently for about 5 minutes, or until the tofu is heated through and the sauce has thickened slightly.
Lower the heat and stir in the vegan sour cream. Season with salt and pepper to taste. Heat the stroganoff until it's warm throughout, being careful not to bring it to a boil after adding the sour cream.
Serve the stroganoff over the cooked noodles, garnished with chopped parsley.