Mix all ingredients (except for defrosted blueberries) together until well combined.
Add mixture to piping bag or ziplock bag (with tip cut off), pipe filling into each donut hole. Add as many blueberries as you want. (Best to pipe, add blueberries, then go onto the next donut.) If you add a ton of blueberries your donuts will have more holes then if you add just a few and push them down into the batter. Your choice, bursting or subtle! Cook mini donuts for 3-4 minutes total (including time to pipe in each donut and fill with blueberries.)
For Glaze:
Combine melted coconut oil with peanut butter and stevia. Using a basting brush glaze the donuts. To harden glaze put glazed mini donuts back in the fridge for at least an hour.