Gather all the ingredients. Bring a pot of water to boil. Blanch the cut broccoli for 30 seconds; add a few drops of sesame oil and a pinch of salt. This helps to add a very basic flavor to the vegetables and keep the colors. Do not overcook the broccoli during this quick blanching process. You want it to remain vibrant green and slightly crisp. Using tongs or a slotted spoon, remove the blanched broccoli from the boiling water and immediately transfer it to the ice bath. Drain and set aside.
Heat a wok or large skillet over medium-high heat. Add cooking oil. Once the oil is hot, add minced garlic. Sauté for 20-30 seconds until they become fragrant and slightly translucent.
Add the sliced mushrooms. Stir-fry for 3-4 minutes until the mushrooms are browned.
Add the broccoli florets and a splash of water to create steam. Cover and cook for 2 minutes or until the broccoli is tender.
Quickly splash the soy sauce, sugar, and oyster sauce over the vegetables. stir-fry for another minute until the veggies are well coated with the sauce.
Season with salt and black pepper to taste. Garnish with some roasted sesame seeds.
Serve your mushroom broccoli stir-fry over white steamed rice. Enjoy!