Add egg yolk, almond flour, oat milk, and honey together and mix well. (If you have vanilla extract, add 3-4 drops.)
Simmer slowly over medium-low heat. (Wait until it thickens gradually, not boiling.)
Let it cool in the refrigerator for about 30 minutes.
Mix Greek yogurt into the cooled mixture, then add sliced banana and egg biscuits, and mix well.
Let it mature in the refrigerator for 1-2 hours before eating.