In Dutch oven over medium-high heat, cook the bacon until brown and crisp, about 7 minutes. Remove the bacon bits and set aside. Leave the bacon fat in the pot.
Add the leek, celery, and carrot and cook uncovered until softened, about 10 minutes.
Add the cremini and shiitake mushrooms; cook uncovered until reduced in size by half, about 5 minutes.
Add garlic, tarragon, thyme, ad salt and cook until fragrant, about 1 minute.
Add broth and coconut aminos, Scrap the bottom of the pot to loosen any bits of vegetables, and the bring the soup to a boil on high heat. Reduce to medium-high heat, add oyster mushrooms, and cook for 3 more minutes.
Turn of the heat and stir in the lemon juice.
Ladle into serving bowls and garnish with the bacon bits and microgreens.
Keeps well in the refrigerator for up to 5 days and in the freezer for up to 3 months.