Preheat oven to 350 F.
Heat butter in a deep skillet. Add quince and cinnamon. Saute on medium high heat for 5 minutes.
Turn off heat. Add yogurt and condensed milk. Stir to combine.
Using a knife, coarsely chop the cheerios. Add butter and mix to combine.
Divide fruit evenly among 7 ramekins. Divide topping evenly on top of the fruit in the ramekins. Place ramekins on a cookie sheet.
Bake for 25-30 minutes, until fruit is bubbly and cheerios is a little browned.
Garnish with whipped cream and decorating sugar.