Measure the cut mango to make sure you have around 2 1/2 cups of flesh (16 oz./ 450 g). Slice more mango for garnish if needed.
Have your serving bowls ready to go. Any glass or small bowl that holds about 2/3 cup of water will work.
Add the mango, sugar, and lemon juice to a blender and blend on high for 1 minute. If using a common mango, check for any remaining fibers. You may need to blend for longer or run the puree through a strainer to filter out the fibers.
Measure out the blended mango, it should be just about 2 cups.
Add the coconut beverage and agar agar to a small pot and whisk them together. Turn the heat to medium-high and bring to a boil, whisking regularly. Once it is boiling, reduce the heat slightly and simmer for 3 to 5 minutes until the agar agar is dissolved completely. You can check that it’s dissolved by dipping a spoon into the liquid and checking for obvious granules.
Add the mango puree and whisk until the mixture is even and smooth. Turn the heat off. Taste the mixture and adjust the taste by adding sugar and/or lemon juice, if needed.
Pour the hot pudding into the serving bowls. (Do not wait for it to cool down, agar agar sets at room temperature so it will begin to set in the pot if you wait to pour it.)
Chill the puddings for 4 hours in the refrigerator. You can let them set at room temperature, but they taste better chilled.
Serve cold or at room temperature with extra sliced mango on top. Enjoy!