Steam broccoli. See note 4.: The aroma of slightly steamed broccoli is green and fresh, and steaming first prevents the vegetable from ending up mushy when it finishes in the pan. Steam until crisp tender so it retains color and bite, then drain well, because excess water will dilute the sauce and steam the shrimp if added wet. A common mistake is under draining, which can make the sauce thin and prevent it from thickening properly.
In a small bowl, add cornstarch and soy sauce. Whisk with a fork until smooth. Add remaining sauce ingredients and whisk again.: You will notice the cornstarch dissolving and the mixture shifting from opaque to sleek and glossy as it combines with the soy sauce and honey . This slurry is what turns into a syrupy glaze when heated. Whisking thoroughly prevents lumps, which would produce an uneven texture in the finished sauce. If you skip whisking, you risk a grainy sauce with pockets of starch.
Add oil to a large nonstick pan over medium-high heat. Add 1/2 of shrimp in an even layer (don’t overcrowd or overlap). Cook for 1 minute, then use tongs to flip on the other side and cook 1 more minute up to 90 seconds or until cooked through. Use tongs to transfer to a plate. Repeat cooking the remaining shrimp and transfer to the plate.: When the oil is shimmering, it gives off a delicate nutty scent if you used sesame oil , and the pan should hiss as the shrimp kisses the surface. Searing creates a faint caramelization and a taut texture on the outside while keeping the interior tender. Flip once to get even color; over flipping cools the pan and prevents browning. A frequent error is overcrowding the pan, which causes steaming rather than searing and yields limp shrimp .
Keeping the heat at medium-high, add the thinly sliced onion. Cook, stirring frequently, for 2–3 minutes or until starting to soften. Add a touch more oil if needed and scrape the bottom of the pan as you cook. Add in garlic and ginger, cooking for another 30 seconds. Finally, add in broccoli and cook to crisp tender.: The pan will smell sweet as the onion softens and takes on color, and the action of scraping the fond releases those browned bits that build flavor. Adding the garlic and ginger briefly ensures they bloom without burning. When you add the pre steamed broccoli , you will hear a quick sizzle and see the florets regain vivacious green tones, indicating they are approaching crisp tender. Be careful not to let the aromatics char, because burned garlic will introduce bitterness and throw off the sauce balance.
Quickly stir up the sauce again (honey usually settles) and add to pan. Cook, stirring constantly, until the sauce thickens like syrup (about a minute). Add the shrimp back in (and any accumulated juices) and toss through just to fully warm the shrimp. Remove from heat, garnish with sesame seeds if desired, and serve immediately! I like this served over cooked rice.: As the sauce hits the hot pan, it will hiss and begin to reduce, transforming into a glossy, syrup like coating that clings to the vegetables and shrimp . Stirring continuously helps it thicken evenly and prevents hotspots where it could scorch. When it reaches a clingy, shiny glaze, return the reserved shrimp and any juices to the pan; the residual heat warms them without further cooking. Overcooking here will toughen the shrimp , so toss just until heated through. A mistake to watch for is letting the sauce reduce too far until it becomes sticky and scorch prone, so remove from heat as soon as it coats the back of a spoon.