Finely grate the zest from the orange half into a medium bowl. Stir in the coconut milk, vanilla extract, salt, oats, raisins, and ¼ teaspoon of the cardamom. Cover and refrigerate the oats mixture overnight.
Divide the oatmeal among four bowls and top it with the bananas, cashews, agave nectar, and remaining ¼ teaspoon of cardamom. Cut the rind off the orange half. Slice between the membranes to release the segments. Chop the segments and evenly scatter orange pieces over each bowl.
Tip: Use dried cherries instead of raisins for a different flavor. You can also replace the light coconut milk with 2% dairy milk if you’d like.