Blueberry Gelee: Mix agar, sugar and water in a sauce pot. Let stand for 5 minutes. Meanwhile, puree blueberries in a blender on high speed until thoroughly liquefied. Strain through a fine sieve, pressing hard on solids. Bring agar and sugar mixture to a simmer and simmer for about 30 seconds, whisking constantly. Whisk agar mixture into blueberry puree. Pour into tilted muffin pan, filling half way. Cool until almost set, about 1 hour.

Lemon Panna Cotta: Dissolve agar and sugar in milk. Let stand for 5 minutes. Meanwhile, mix lemon juice, zest, and yogurt. Heat milk and sugar to simmer and simmer for 10 seconds, whisking constantly. Remove from heat and whisk in yogurt mixture. Carefully pour into muffin tins.