Caramelized Apple Parfaits

Line a colander or sieve with cheesecloth or a coffee filter and set it over a bowl. Spoon in yogurt and let drain for about 30 minutes.

Meanwhile, stir together sugar and water in a medium heavy saucepan. Bring to a boil, stirring to dissolve the sugar. Cook, without stirring, until the syrup turns deep amber, about 5 minutes. (Do not let the syrup burn.) Remove the pan from the heat, add butter and swirl the pan until the butter has melted.

Add apples and lemon juice. Return to low heat, cover and cook for 5 minutes. Uncover, and cook, stirring occasionally, until apples are tender and translucent and the juice has thickened slightly, 15 to 20 minutes. Let cool slightly, about 5 minutes.

Spoon alternating layers of the caramelized apples and drained yogurt into 4 parfait or wineglasses. Sprinkle walnuts over top, if desired.