Thai curry paste, not to be confused with curry powder, is a blend of chile peppers, garlic, black pepper, coriander, and other ingredients. It comes in green and red varieties, which you'll find in the international aisle -- for this recipe, choose green.
1 medium onion (1/2 inch thick), halved and sliced
1 to 2 tablespoons Thai green curry paste
4 roasted chicken breasts (about 1 1/2 pounds), skin and bones removed, meat cut into 1-inch pieces
1 can (14.5 ounces) coconut milk
1 cup torn fresh basil leaves
2 tablespoons fresh lime juice (from 1 lime)
Cook rice according to package instructions. Meanwhile, place cornstarch in a small bowl; whisk in 2 to 3 tablespoons chicken broth until smooth (reserve remaining broth). Set aside.
Heat oil in a large skillet over medium. Add green beans and onion; cook, tossing frequently, until they begin to soften, 5 to 7 minutes.
Add curry paste to green beans and onion in skillet. Cook, stirring and scraping bottom of skillet, until paste is slightly darkened, 3 to 4 minutes. Add chicken, coconut milk, cornstarch mixture, and reserved chicken broth. Simmer until vegetables are tender and sauce is slightly thickened, 5 to 8 minutes.
Add basil and lime juice. Season with salt, and stir to combine; serve over rice.