Add blueberries, nondairy milk, and stevia to a blender and pulse. You still want your blueberries to be a little chunky so that you have a bit of a bite in your oatmeal. You can also start with less milk and add more if needed. This is completely based on personal preference, but you can see I like mine with quite a bit of liquid.
Divide mixture evenly between three mason jars (or whatever container you have on hand).
Add 1/2 cup of oatmeal to each serving
Divide the lemon zest evenly amongst the containers
Store for at least an hour and up to five days in the fridge before eating. You can either enjoy it cold or do as I do and heat it for 30 second or so.