Prep mushrooms – Cut mushrooms into medium chunks (leave them big if you like them meaty).
Sauté mushrooms – Heat olive oil in a deep skillet. Add mushrooms in stages—start with the firm ones like champignons—and brown them lightly.
Add flavor – Stir in spices and miso paste, coating the mushrooms well.
Cook noodles – Add rice noodles, followed by hot water (just enough to barely cover or sit 1 cm / 0.5" above). Cover with a lid.
Prep greens – While it simmers, chop spinach if using fresh.
Stir and steam – Open lid, gently mix noodles, and re-cover. Repeat until noodles are just softened, about 8 minutes total.
Finish it up – Pour in coconut milk and stir through. Mix in spinach last so it stays vibrant and fresh.
Serve – Plate hot and top with nutritional yeast, chili flakes, walnuts (if using), fresh parsley, or scallions.