Agar-agar is a vegetable-based gelatin that is widely available in Asian grocery stores and health food stores.
To get 1 cup (250 ml) of raspberry purée, blend 2 ½ cups (315 g) of thawed frozen raspberries in a blender. Strain through a sieve to remove the seeds.
Raspberry powder is available in some grocery stores in the health food and organic aisles.