- For the crust, mix coconut flour, almond flour, allulose, cinnamon, and half teaspoon xanthan gum in a medium bowl.
- Use a pastry blender to incorporate the butter until you have a crumbly texture. Reserve half cup of this mixture for the top.
- To the remaining crust, add the beaten egg and mix well.
- Press this mixture into the bottom of an 8x8 baking dish. Set aside.
- For the filling, combine the blueberries and rhubarb in medium bowl.
- In a small bowl, mix the allulose and half teaspoon of xanthan gum. Mix well. Pour over fruit and combine.
- Pour fruit mixture onto the crust.
- Sprinkle remaining crust mixture on top of the fruit.
- Cover with foil and bake at 400 degrees for 40 minutes.
- Remove foil and bake an addtional 5 minutes or until crust is lightly browned.
