Start by toasting cumin and coriander seeds in a dry skillet over medium heat until fragrant, about 1-2 minutes. Then, transfer them to a mortar and pestle or spice grinder and grind into a fine powder.
Peel and devein the shrimp if needed, then pat them dry thoroughly with paper towels. This helps them sear nicely without steaming.
Heat 2 tablespoons of neutral oil in your large skillet or wok over medium heat until shimmering. Add a tablespoon of your freshly ground spice mixture and cook for about 30 seconds until fragrant, stirring constantly to prevent burning.
Add the diced onion to the pan and cook for 5-7 minutes, stirring occasionally, until translucent and soft, with some golden edges forming. The aroma should be sweet and spicy.
Stir in the remaining curry paste ingredients—garlic, ginger, turmeric—and cook for another minute until the mixture is fragrant and slightly darker in color.
Pour in the full-fat coconut milk, stirring well to combine. Bring the mixture to a gentle simmer and let it bubble softly for about 5 minutes, allowing the flavors to meld and the sauce to thicken slightly.
Increase the heat slightly and add the shrimp in a single layer, pressing them into the sauce. Cook for 3-4 minutes, flipping once, until they turn pink and opaque, and are just cooked through.
Finish by squeezing in the fresh lime juice and sprinkling chopped cilantro over the curry. Taste and adjust seasoning with salt or more lime if needed.
Remove from heat and let the curry rest for a minute or two. Serve hot, garnished with extra cilantro, alongside steamed rice or warm naan for a complete meal.
