Place the yogurt in a strainer
lined with a paper towel and let it drain
over a bowl to thicken in the refrigerator for at least 4 hours, and up to 1 day. Discard the liquid and set the thickened yogurt aside.
Puree half the raspberries
in a food processor
until smooth. Strain into a large bowl, pressing the liquid out with a rubber spatula
. Discard the seeds. Whisk
in the confectioners' sugar. Stir in the remaining raspberries.
In a chilled small bowl whip
the cream until stiff peaks are formed. Gently fold in the yogurt
. Fold in the raspberry
Spoon into cocktail
glasses and chill, covered, for at least 1 hour. Serve with ladyfinger