Preparation Toast coriander, cumin, cinnamon, and cloves in a small heavy skillet over medium heat, shaking skillet, until fragrant and darker (do not burn), 3 to 4 minutes. Stir in coconut, red-pepper flakes, and turmeric and cook, stirring, until coconut is golden brown, 1 to 2 minutes. Transfer to a bowl and cool completely, then pulse in grinder until finely ground. Heat oil in a 12-inch heavy skillet over medium-high heat until it shimmers, then sauté onion until golden, 3 to 5 minutes. Add garlic, ginger, chiles, tamarind, and spice mixture and cook, stirring, 30 seconds. Add tomato and cook, stirring, until sauce is thickened, 3 to 4 minutes. Toss shrimp with sea salt, then add to sauce and cook, stirring, until just cooked through, 3 to 5 minutes. Stir in vinegar and season with sea salt. Cooks' note:If you can't find tamarind concentrate at your Asian market, use 3 tablespoons tamarind pulp (from a pliable block) softened in 6 tablespoons hot water, stirred into a paste, then forced through a sieve.
Preparation Toast coriander, cumin, cinnamon, and cloves in a small heavy skillet over medium heat, shaking skillet, until fragrant and darker (do not burn), 3 to 4 minutes. Stir in coconut, red-pepper flakes, and turmeric and cook, stirring, until coconut is golden brown, 1 to 2 minutes. Transfer to a bowl and cool completely, then pulse in grinder until finely ground. Heat oil in a 12-inch heavy skillet over medium-high heat until it shimmers, then sauté onion until golden, 3 to 5 minutes. Add garlic, ginger, chiles, tamarind, and spice mixture and cook, stirring, 30 seconds. Add tomato and cook, stirring, until sauce is thickened, 3 to 4 minutes. Toss shrimp with sea salt, then add to sauce and cook, stirring, until just cooked through, 3 to 5 minutes. Stir in vinegar and season with sea salt. Cooks' note:If you can't find tamarind concentrate at your Asian market, use 3 tablespoons tamarind pulp (from a pliable block) softened in 6 tablespoons hot water, stirred into a paste, then forced through a sieve.