Whisk the eggs in a small bowl and set the bowl next to your stove. Slice the vanilla bean pod in half lengthwise, then, using the tip of a paring knife, scrape out the seeds. Put the scraped- out seeds, bean pod, coconut milk, and water in a saucepan and heat slowly over medium heat, stirring often.
Once the mixture begins to simmer, stir more frequently; continue to simmer for 5 minutes. Remove the vanilla bean pod and discard. Slowly pour a ladleful of the hot coconut milk mixture into the eggs as you whisk rapidly to incorporate. Then pour the coconut-egg mixture back into the saucepan while continuing to whisk. Stirring occasionally, cook for 5 to 10 minutes or until a spoon remains coated when dipped into the mixture.
Pour the entire mixture into a blender, add the banana, and blend until smooth, approximately 1 to 2 minutes. Add the cinnamon, salt, and chia seeds and pulse a few times or until evenly dispersed.
Divide the mixture into 4 serving bowls, jars, or glasses; cover; and refrigerate for at least 3 hours, preferably overnight. Garnish with chopped nuts, banana slices, or more coconut milk poured over the top. To serve warm, reheat in a saucepan over low heat until warmed through.
Omit the eggs. Blend all the ingredients in
a blender, adding the chia seeds at the very end. Pour into containers and refrigerate for at least 4 hours. The consistency will be more like yogurt.