When the oil is hot, add the onion, garlic, mushrooms and a good pinch of salt and give them a quick mix.
Add the wine and mix well for a few seconds to cook out the alcohol.
Add the carrots, celery, thyme and garlic and mix well. Add the soy sauce, tomato paste, ⅓ tsp salt (if using water or unsalted broth) and water/broth and give it a mix. You can also add in 1 bay leaf and some rosemary for flavor variation at this point.
Meanwhile, boil the potatoes and cauliflower in a pot and prepare as you do mashed potatoes.
Add cornstarch slurry to the mushrooms and give it a mix (you can also add 2 tbsp of the mashed potato mixture to thicken). Add spinach or baby kale and black pepper and mix. Bring the mixture to a boil to thicken.
Serve the mash layered with the mushroom bourguignon. Garnish with some fresh thyme or basil and black or white pepper.
