Pat the shrimp dry with paper towels.: The surface feel should change from damp to slightly tacky, and you will notice that the paper towels pick up a fair bit of moisture. Drying is essential because moisture blocks browning, creating steam instead of a proper sear. If you skip this, the shrimp will steam and fail to caramelize, resulting in a softer, less flavorful texture. A common mistake is rushing this step, so take a moment to press gently and rotate the shrimp until they feel consistently drier.
Combine the tamarind pulp with water. Extract the juice and discard the pulp.: As you stir the tamarind pulp into the water , the liquid will darken and smell tangy and fruity, like citrus with molasses notes. Pressing or squeezing the mixture helps release fragrant, sour juices that form the base of the marinade. Straining produces a clear, deep amber liquid; keeping solids would make the marinade gritty and uneven. If your strained juice seems weak, it may be from overly cold water, so let the mixture sit a few minutes at room temperature to extract more flavor.
Combine the tamarind juice with the remaining marinade ingredients and mix with the shrimp. Marinate for 5 to 10 minutes.: Once the tamarind juice meets the fish sauce , sugar , turmeric powder , cayenne pepper powder , and oil , you will notice an aromatic lift, with salty and smoky notes balancing the sour. Toss the shrimp so each piece glistens; you should see a light coating rather than a puddle of liquid. Marinating briefly seasons the surface without breaking down the protein, which keeps the texture snappy. Leaving them too long can make the texture a bit mushy, so stick close to the 5 to 10 minute window for best results.
Grill or pan-fry the shrimp. If grilling, brush some oil on the surface of the shrimp.: Heat is where flavor concentrates, so whether you hear an immediate sizzle on the skillet or the grill marks form, those sounds tell you the sugars and proteins are caramelizing. On the grill, brush a touch of oil to prevent sticking and encourage even browning; in the pan, a thin film of oil will give you that crisp edge. The shrimp will change from translucent to opaque and take on golden edges; this visual shift is your cue that they are nearly done. Overcooking makes shrimp rubbery, so stop as soon as they curl into gentle C shapes and lose translucency.
Thread a piece of pineapple onto a short bamboo skewer, followed by the shrimp. Garnish with ground peanuts and chopped scallions.: When assembling, the contrast is immediate: warm, slightly charred pineapple releasing sweet steam, and hot, fragrant shrimp threaded beside it. The aroma of toasted meat and caramelized fruit should be pronounced, and the final sprinkle of ground peanuts adds a nutty perfume while crunchy scallions provide a fresh, green lift. Serve right away because the temperature and textures are at their peak; letting skewers sit will soften the crisp edges and dull the fresh notes.