Simmer on stove the milk, maple syrup, lemon peels, and agar powder. Do not boil. Stir and keep on simmer until solution seems completely combined. It took me about 2-3 minutes.
Remove lemon peels. Fill 3 small shot or yogurt glasses. Let jars cool to room temperature and then refrigerate 1-2 hours or until panna cotta sets (it doesn't slosh when you move jars). It might take longer to set, there are a lot of influencing factors. If you want to be sure it will set in time, make it the day before and let it set overnight.
Make Mango Puree
Heat in pan the chopped mango, maple syrup, and water. Mash mango with a fork as it gets mushy.
Simmer sauce a few minutes until it appears to thicken. It took me about 2 ½ minutes. Let sauce cool to room temperature. Stir in lemon juice.
Assemble & Serve Panna Cotta
Spoon puree in even amounts on top of each chilled panna cotta. Decorate with sliced lemon.
Both recipes can be kept refrigerated overnight for best taste.