Bring a medium pot of salted water to a rolling boil. Add the broccoli florets and blanch 90 seconds — bright green and just starting to soften, still firm. Drain immediately and pat very dry with a clean towel or paper towels. Dry florets char; wet florets steam.

Pat the shrimp very dry and toss with the 2 tablespoons cornstarch and 1/4 teaspoon of the salt. In a small bowl, whisk together the soy sauce, honey, rice vinegar, sesame oil, the 1 tablespoon water, and the 1 teaspoon cornstarch until smooth.

Heat 1 1/2 tablespoons of the oil in the wok or skillet over high heat until it shimmers and just starts to smoke. Add the shrimp in a single layer and sear undisturbed 90 seconds per side, until pink, opaque, and curled into loose C-shapes. Transfer to a plate — they'll finish in the glaze.

Add the remaining 1 1/2 tablespoons oil to the same wok over high heat. Add the blanched broccoli in a single layer and cook undisturbed 2 minutes, then toss and cook 1–2 minutes more, until the edges are deeply charred in spots and the florets are crisp-tender.

Push the broccoli to the sides and reduce the heat to medium. Add the sliced garlic and chili flakes to the center of the pan with a drizzle of oil if the pan looks dry. Stir constantly 30–45 seconds, just until the garlic turns pale gold and smells intensely fragrant — not brown.

Return the shrimp to the wok. Give the sauce a final whisk (cornstarch settles) and pour it over everything. Toss 1–2 minutes, until the glaze thickens to a glossy sheen that coats the shrimp and broccoli. Finish with the scallions and the remaining 1/4 teaspoon salt if needed. Serve over rice, scattered with sesame seeds and extra chili flakes.