Preheat your wok or skillet over high heat until it’s just about smoking, which takes about 2 minutes.
Add the oil to the hot pan, swirling to coat the surface evenly. When it shimmers and begins to crackle, toss in the minced garlic and cook for about 15 seconds until fragrant and golden.
Add the sliced mushrooms and stir constantly, allowing them to brown and release their earthy aroma, about 2-3 minutes. They should become golden and slightly shrunk, with a smoky scent filling the air.
Next, add the broccoli florets to the pan, tossing them quickly to coat with oil and garlic. Stir-fry for 3-4 minutes, maintaining high heat, until the broccoli turns bright green and just starts to caramelize at the edges.
Pour the soy sauce into the pan, swirling to coat all the vegetables evenly. Continue stir-frying for another 1-2 minutes until the sauce glazes the veggies and they are tender yet still crisp.
Sprinkle in red pepper flakes if using, and toss everything again to distribute the heat evenly. Remove from heat once the vegetables are perfectly cooked and the sauce has thickened slightly, filling your kitchen with a savory aroma.
Transfer the stir fry to a serving dish, sprinkle with sesame seeds if desired, and enjoy immediately while warm and vibrant.
