Whisk together 1/2 cup honey, 1/3 cup rice vinegar, 1 tablespoon soy sauce, 3 tablespoons tomato paste, and 3 tablespoons pineapple juice in a medium bowl. Whisk together 1 tablespoon cornstarch and 2 tablespoons water in a separate small bowl.: Before you turn on the heat take a deep breath and inhale the mix of sweet and tangy aromas as you whisk the sauce components together, the glossy honey and thick tomato paste coming together into a rich colored emulsion. The sound is subtle here, just the soft clink of whisk against bowl, but the real sensory cue is the smell, a bright pineapple top note balanced by the savory umami of soy sauce . Mixing a separate cornstarch slurry ensures the sauce will thicken smoothly when heated without forming lumps, and it is why I always make it in its own bowl. A common mistake is adding cornstarch directly to a hot sauce which makes clumps, so keep it separate until the sauce is warm. Take a moment to taste a tiny smear on the spoon so you understand the sweet to tang ratio and adjust if needed.
Dry the 1 pound peeled and deveined shrimp with paper towels. Combine shrimp with 1/2 teaspoon kosher salt and 1/4 teaspoon black pepper in a medium bowl.: Drying the shrimp is a tactile step, you will notice the difference between slick and dry flesh, and dryness will help achieve a proper sear. When you season with kosher salt and black pepper , the salt penetrates briefly and seasons the meat while the pepper gives an aromatic edge. The smell of the fresh shrimp changes subtly as the salt draws moisture to the surface, so be quick to pat them again if they release water. A common error is overcrowding the bowl with liquid marinate, which prevents proper searing, so keep the seasoning minimal and direct.
Heat a wok or large saute pan over medium-high heat. Add HALF of the 2 tablespoons vegetable oil, and the 1/2 teaspoon sesame oil.: Heating the pan properly is an auditory and visual cue, you want to see a faint shimmer on the oil and possibly a whisper of smoke at the lip of the pan. Adding half the vegetable oil with the sesame oil gives you both the high heat tolerance and the toasted aroma. The scent of sesame oil blooming is immediate and pleasing. If the pan is not hot enough the shrimp will steam, so be patient and get it hot first. Avoid adding cold ingredients that will drop the pan temperature too much.
Once the oil is hot, add the shrimp in a single layer and do not move for 1 minute. Stir and cook for another 30 seconds until the shrimp is opaque and pink. Transfer the cooked shrimp to a clean plate.: You will hear a bright sizzle when the shrimp hits the pan, and resisting the urge to move them lets a thin sear form, lending texture and nutty browned notes. The visual cue is a change from translucent to opaque, with a pink hue and curled shape. Shrimp overcook quickly, so timing here is everything; an extra 30 seconds can make them rubbery. A common mistake is crowding the pan, which produces steam instead of sear, so work in batches if needed. Once cooked, transfer them to a warm plate to rest briefly while you cook the vegetables.
Add the remaining vegetable oil to the pan and heat. Once the oil is hot, add the 1 cup diced red bell pepper, and 1 cup sliced zucchini. Cook for 2 minutes, stirring frequently.: The vegetables will hit the hot oil with a bright sizzling sound and a fragrant sweetness will lift from the pan. As you stir, watch for the edges of the red bell pepper to soften and the zucchini to develop a faint golden edge while remaining firm in the center. This step is about texture contrast, you want a quick tender crispness rather than a soft, lifeless vegetable. A frequent oversight is overcooking the vegetables until they lose color and snap, so stick to the brief cooking window and keep them moving.
Add in the 2 teaspoons minced garlic and 1 teaspoon minced ginger, stir-fry for 30 seconds. Add in the 1 cup pineapple chunks and stir-fry for another 30 seconds.: When you add the garlic and ginger the pan will erupt with aromatic notes, a warm pungency that perfumes the oil. Stir briefly to avoid browning the garlic, which can become bitter. Adding the pineapple releases a burst of fruity steam and a quick caramelization may begin on the fruit edges, adding a wonderful complexity. Work quickly and keep the pieces moving so nothing burns, and watch for a syrupy sheen starting to form around the fruit.
Pour the sweet and sour sauce over the vegetables and pineapple, stir, and cook until simmering, 2 minutes.: As the sauce hits the hot pan you will hear a steady bubbling and smell the melding of sweet and tangy elements. The sauce will thin at first then begin to reduce and concentrate, coating the vegetables and pineapple with a glossy finish. Simmering helps meld flavors so the acidity softens and the sweetness rounds out. A typical mistake is simmering too long which can over reduce and make the sauce too thick and overly sweet, so watch the pan and stir gently to encourage even heating.
Gradually whisk the cornstarch mixture into the sauce and stir constantly until the sauce is thickened, 30 seconds.: Adding the cornstarch slurry slowly while stirring creates a velvety, clingy glaze. The texture shifts quickly from thin to syrupy, and you will see the sauce take on a clear, shiny appearance. Keep stirring to avoid lumps and to monitor the thickness so you do not end up with a glue like consistency. If the sauce becomes too thick, a splash of water can rescue the texture, which is a fix I often use. The right thickness is when the sauce coats the back of a spoon and drips slowly.
Add the cooked shrimp back to the pan, stir to combine, and cook until shrimp are warmed through, 2 minutes.: Reintroducing the shrimp brings back that satisfying sizzle and the aroma of cooked seafood infused with glaze. The shrimp will warm quickly and absorb the flavors from the sauce; you will see the liquid cling to the curved shapes and glisten. This short final heat allows flavors to meld without overcooking the protein. Avoid leaving the pan on high heat too long, which can toughen the shrimp .
Serve sweet and sour shrimp garnished with 1 tablespoon sliced green onion and 1/4 teaspoon sesame seeds.: The finishing garnish adds fresh color and a mild sharpness from the green onion , while the sesame seeds deliver a tiny nutty crunch. Serve right away while the sauce is glossy and warm, and plate so each portion gets a balance of shrimp , vegetables, and fruit. A common serving mistake is letting the dish sit too long which dulls the glaze and softens textures; serve promptly for best results.