Combine the crust ingredients in a food processor and pulse until the dough forms a ball. This may take 2-3 minutes. Chill the dough while you make the fillings.
Fillings:
To make the strawberry and/or blueberry filling heat the berries and sweetener over medium heat until the sweetener dissolves. Transfer to a small blender or food processor and process until smooth. Add the xanthan gum.
To make the brown sugar cinnamon filling simply stir together the ingredients.
Assembly:
Preheat the over to 350.
Roll out the dough between two pieces of greased parchment paper. Cut 2x3 inch rectangle with a pizza cutter. Reroll the extra dough and make more rectangles until it is all used up.
Place one piece of the parment you were using on a cookie sheet. Gently transfer half of the rectangles to the prepared baking sheet.
Top each of the bottom rectangles with a tablespoon of filling. Cover with a top rectangle. Press the edges together with your fingers. Use a fork to poke a few holes in the top of the pastry and to crimp the edges.
Bake for 15-20 minutes or until golden brown. Top with icing and sprinkles if desired.
Icing:
Mix together the powdered sweetener and butter. Thin with almond milk a little at a time until you reach a spreadable consistency. Spread on the cooled pop tarts.
Notes
Nutrition: the nutrition facts are for one pastry with strawberry filling. They will vary slightly based on the filling used. There are 3.3 NET carbs per pastry.Fillings: if you want to make more than one filling you can half the filling ingredients. Each type of filling can fill all 8 pastries as written.Substitutions: swap the strawberries or blueberries for raspberries or blackberries. To Reheat: you can eat them at room temperature or warm them for 10-15 seconds in the microwave. Just wrap in a paper towel before reheating. To Freeze: flash freeze on a baking sheet then put in a larger bag or container. They will stay fresh in the freezer for up to 2 months. Notes on Sweeteners: