1. Hydrate dried mushrooms by soaking in warm water as per package instructions. Set aside the soaking liquid for later use.
2. Pulse fresh mushrooms in a food processor or multi-chopper until they are finely minced.
3. Finely dice the onion.
4. Heat olive oil in a large skillet and sauté the onions until they become translucent.
5. Add minced garlic, reduce heat, and ensure the garlic does not burn.
6. Add parsley and rosemary, and sauté for an additional minute.
7. Combine all the mushrooms into the skillet, coating them in the seasoned oil, and brown.
8. Season with salt and black pepper to taste.
9. Stir in onion powder, garlic powder, and cumin.
10. Allow the mushrooms to cook until the fresh ones release their liquid, which takes approximately 10 minutes.
11. In a separate bowl, whisk the cornflour into the water, vegetable stock, or soaking liquid from the dried mushrooms. Stir the mixture into the skillet, optionally adding vegan Worcestershire sauce.
12. Continue cooking until the liquid has significantly reduced, which takes another 5-10 minutes.
13. Taste and adjust the seasoning with salt and pepper as needed before serving.