Put the frozen raspberries
into a blender
with the sugar
, and puree. You may have to be patient as they will be difficult to blitz at first since they are extremely hard when frozen.
Spoon 1 to 2 teaspoons of the raspberry
puree into each glass, top with 2 tablespoons of the yogurt
and sprinkle a layer of cookie
crumbs on top.
Cover the crumbs with 1 more layer of yogurt, then raspberry puree and finally cookie crumbs again.
These can be prepared the night before, in which case don't sprinkle the final layer of cookie crumbs until you are ready to eat the swirls but leave the glasses with the yogurt on top, covered with plastic wrap