Preparation Heat oil in a 12-inch heavy skillet over medium-high heat until it shimmers, then sauté chicken with 1/4 teaspoon salt until golden brown and just cooked through, 4 to 6 minutes. Transfer to a bowl. Simmer soup in skillet with curry paste and pineapple chunks, uncovered, stirring occasionally, until liquid is reduced by about one fourth, about 5 minutes. Return chicken with any juices from bowl to skillet and stir in mushrooms, then simmer 1 minute.
Preparation Heat oil in a 12-inch heavy skillet over medium-high heat until it shimmers, then sauté chicken with 1/4 teaspoon salt until golden brown and just cooked through, 4 to 6 minutes. Transfer to a bowl. Simmer soup in skillet with curry paste and pineapple chunks, uncovered, stirring occasionally, until liquid is reduced by about one fourth, about 5 minutes. Return chicken with any juices from bowl to skillet and stir in mushrooms, then simmer 1 minute.