Combine all sauce ingredients in a bowl, whisk well, and set aside.
Wash and rinse the broccoli under running water. Heat a pot of water and bring it to a boil. Cook the broccoli florets for 1 minute, then transfer them to a bowl of ice-cold water. Let them cool for 5 minutes, then drain and set aside.
Rinse and pat the shrimp dry with paper towels. Heat a wok or skillet over high heat and add the oil. Once the oil is hot, add the garlic and stir-fry until aromatic or light brown. Add the shrimp and stir a few times until cooked through and pink.
Turn the heat to medium-low. Add the broccoli and sauce, stirring continuously for 1 minute until the sauce thickens. Turn off the heat and transfer to a serving dish. Serve immediately.Pro tip: Give the sauce a quick stir before pouring it into the wok.