Place the egg whites into a stand mixer and whip until stiff peaks form. Set aside.
In another bowl, whisk the yolks and remaining ingredients together except blueberries.
Fold the egg whites a little at a time into the batter until just combined.
Grease the crock pot and pour the mixture into the pot.
Sprinkle the blueberries over the batter.
Cover and cook on low 3 hours or until a toothpick come out clean.
Allow to cool with cover off for 1 hour then place in the refrigerator to chill for 2 hours or overnight.
Serve cold with a little sugar free whipped cream if desired.
Cover with plastic wrap or store in an airtight container in the fridge for up to 5 days.