Step 1 In a large, heavy-bottomed saucepan, combine the sugar and water. Add the quince and stir to coat.
Step 2 Heat the mixture over medium heat until the sugar melts completely and begins to bubble, stirring often so the fruit does not burn. Reduce the heat to maintain a very gentle simmer and continue to cook, stirring occasionally, until the fruit is softened and turned to a rich rose or red color and the sugar has reduced to a thickened, syrupy consistency, about 1 1/4 hours. Remove from heat.
Step 3Serve with a little heavy cream or yogurt spooned over top, or use as a topping for vanilla ice cream.