This sugar-free blueberry crumb cake recipe is perfect for those who are watching their sugar intake. Made with almond flour, coconut flour, and fresh blueberries, this cake is a healthier alternative to traditional crumb cake. The crumb topping is made with almond flour, coconut oil, and stevia, making it a delicious and sugar-free addition to the cake. This recipe is easy to make and can be enjoyed by those who are following a sugar-free or low glycemic diet.