Begin by chopping the broccoli into bite-sized florets and slicing the mushrooms thinly. Mince the garlic and set all ingredients aside for easy access during cooking.
Heat the wok or skillet over medium-high heat and add vegetable oil. Once shimmering, add the minced garlic and sauté until fragrant, about 30 seconds, releasing a fragrant aroma and slightly turning golden.
Add the broccoli florets to the pan, stirring quickly to coat with garlic and oil. Cook for about 2-3 minutes until the vegetables turn bright green and start to soften, maintaining some crunch.
Next, toss in the sliced mushrooms and stir to combine. Cook for another 3-4 minutes, allowing the mushrooms to release moisture and become tender, while the broccoli stays crisp.
Pour in the soy sauce and drizzle the sesame oil over the vegetables. Toss everything together, ensuring the sauce evenly coats each piece, and cook for an additional 1-2 minutes until the vegetables are glazed and heated through.
If desired, sprinkle red pepper flakes for heat, and give the stir fry a final toss. Remove from heat once the sauce thickens slightly and the vegetables are vibrant and glossy.
Serve hot straight from the pan, enjoying the crispy-tender vegetables with the flavorful coating, perfect for pairing with rice or noodles.