Combine water, cornmeal, whole milk, coconut milk, white sugar, vanilla extract, salt, nutmeg, and cinnamon in a blender; blend until smooth.
Bring the mixture to a boil in a saucepan; whisk occasionally until beginning to thicken, about 5 minutes. Reduce heat when slow bubbles form. Stir frequently until as thick as you like, about 5 minutes. Add raisins.
Remove from heat, cover, and let cool before serving, about 5 minutes.