Gather your wok or large skillet and set it over high heat until shimmering, which should take about 2 minutes.
Add a tablespoon of vegetable oil, swirling it to coat the surface evenly. Wait until the oil just begins to smoke slightly, indicating it's ready for stir-frying.
Toss in the minced garlic and chopped shallot, stirring quickly until fragrant and just beginning to turn golden, about 30 seconds. The kitchen will fill with a savory aroma.
Add the sliced wild mushrooms to the pan, spreading them out so they can caramelize without crowding. Let them cook undisturbed for a couple of minutes, then stir and cook until tender and browned, about 5 minutes. You'll notice their earthy scent deepening as they cook.
Push the mushrooms to one side of the pan. If needed, add a little more oil, then add the cold, day-old rice, breaking up any clumps with your spatula. Fry without stirring for 1-2 minutes until the rice starts to crisp and turn golden.
Stir the rice and mushrooms together, mixing evenly. Drizzle the soy sauce over the mixture and stir to coat all the ingredients thoroughly. Let everything fry for another 2-3 minutes, allowing the rice to absorb the flavors and develop a smoky aroma.
Remove the pan from heat and splash the sesame oil over the rice. Toss in the sliced green onions and give everything a final stir, brightening the dish with fresh flavor and a pop of color.
Serve the mushroom fried rice immediately in warm bowls, garnished with additional green onions or sesame seeds if desired. The rice should be crispy on the edges, tender mushrooms, and fragrant with umami and sesame aroma.
