Can I make this soup ahead of time?
Yes. Prepare the soup base (everything except cream and crispy mushrooms) up to 2 days ahead. Stir in heavy cream just before serving, then top with freshly crisped oyster mushrooms.
What type of mushrooms work best for crisping?
Oyster mushrooms are ideal because they crisp quickly and stay crispy. King trumpet, shiitake, or cremini can substitute, though they may not achieve the same delicate crispness.
How do I know when the roux is cooked properly?
Cook the butter and flour mixture for 1–2 minutes over medium heat, stirring constantly. It should smell nutty and slightly toasted, but not brown, before adding stock.
Can I substitute the miso paste?
Miso adds umami depth and is not easily replaced. You can omit it, but add 1/2 tsp soy sauce or a parmesan rind to compensate for savory complexity.
How do I make the oyster mushrooms crispy?
Slice thin, pat dry, then either sauté in oil over high heat until golden and crispy (3–4 minutes), or bake at 400°F on parchment until edges brown (8–10 minutes).