Gather your equipment: a large wok or wide skillet, a spatula, and a sharp knife for prep.
Trim the tough ends off the asparagus, about 1-2 inches, then cut into 2-inch pieces for quick cooking.
Gently clean the mushrooms with a damp cloth, then slice them to match the size of the asparagus pieces.
Preheat your pan over medium-high heat until hot and shimmering with oil.
Add 1-2 tablespoons of neutral oil to the pan, swirling to coat the bottom. When it shimmers, add the sliced mushrooms.
Sauté the mushrooms, stirring often, for about 3-4 minutes until they turn golden brown and release their earthy aroma.
Add the asparagus pieces to the pan and stir well. Cook for another 2-3 minutes until the asparagus turns bright green and is tender yet still crisp.
Push the vegetables to one side of the pan, then add the minced garlic to the empty space. Sauté for about 30 seconds until fragrant, stirring quickly to prevent burning.
Mix everything together, then pour in the soy sauce and drizzle the sesame oil. Toss to coat all ingredients evenly, watching for a slight sizzle.
Sprinkle the red pepper flakes over the stir fry, and cook for another minute to let the flavors meld and the sauce thicken slightly.
Remove from heat, taste, and adjust seasoning if needed. Let rest for a minute to allow the flavors to settle.
Serve immediately, garnished with a sprinkle of sesame seeds or chopped scallions if desired. Enjoy the vibrant crunch and savory aroma of this simple stir fry.