Creamy Miso Mushroom Sauce

Ingredients -- non-Vegetarian

1/2 cup beef stock (a vegan could try this with vegan soup stock)
14 oz mixed Mushrooms, cut in half
2 oz unsalted butter
1 cup heavy cream
2 Tbsp white miso paste (also known as "shiro miso")
2 Tbsp vegetable oil
2 cloves Garlic, finely chopped
1 shallot, finely chopped
3 Thyme sprigs
1/2 cup saké (or use dry white wine if saké not available)
2 Tbsp chives, finely chopped
zest of half a lemon
white pepper to taste (~ 1/2 tsp); sea salt to taste

Place the beef stock in a small saucepan over medium-high heat. When just simmering, whisk in the miso paste. Once combined, remove from heat.
Heat the oil in a large frying pan over high heat. When hot, add the mushrooms and spread them out in the pan. Sprinkle with salt and allow the mushrooms to sear without moving them. After about 2 minutes you should have some nice color on the first side. Flip the mushrooms over and sear another 2-3 minutes. Now add the butter, garlic and shallots. Cook, stirring for half a minute. Then add in the thyme sprigs.
Now pour in the saké and allow to bubble and simmer for a minute. Then add the beef stock mixture and the cream. Simmer for 4-5 minutes or until thickened slightly. Stir in the pepper, lemon zest and chives. Remove from heat. When cool-ish, blend in blender for smooth texture (optional). Serve warm. If the sauce is refrigerated and thickens, stir in a couple of tablespoons of water or beef stock to loosen.