Make sure your squid is cleaned. You can slice it into rings or cut it open.
Heat 1 tbsp of oil in a wok or large pan over medium-high heat. Add the squid and pan-fry quickly for about 1−2 minutes until it just curls and turns opaque. Do not overcook it! Remove the squid immediately and set it aside.
Wipe the pan clean. Add 2 tbsp of oil and heat over medium heat. Add the minced garlic, shallot, scallion white, and fresh chili. Fry until fragrant, about 30 seconds to 1 minute.
Pour in the 150 ml of tamarind juice.
Add the fish sauce, oyster sauce, sugar, and chili paste. Stir everything together well.
Bring the sauce to a boil, then reduce the heat to a simmer. Allow the sauce to reduce for several minutes until it thickens slightly and coats the back of a spoon. This concentrates all the amazing sweet-and-sour flavor!
Once the sauce has reduced to your liking, add the pan-fried squid back into the pan.
Quickly toss the squid in the tamarind sauce and mix well.