Preheat the oven to 380 degrees Fahrenheit and select a muffin tray.
To prepare the pastry, add the ground almond, flax, one tablespoon of erythritol, one teaspoon of cinnamon, butter and salt to a food processor. Blend to form a chunky crumb.
Add one egg and blend again to form a dough.
Take 3/4 of the dough and divide into 6 even portions. Press each portion of dough into the base of a muffin cup, forming 6 pastry cases.
Transfer to the oven to bake for 8 minutes until lightly golden.
Whilst the pastry is baking you can prepare the filling. Add the rhubarb to a small pan along with the cranberries, water, remaining cinnamon, ginger, nutmeg, cloves, orange zest and remaining erythritol.
Bring the mixture to a boil and mash the fruit with a fork. Reduce to a simmer for ten minutes until you have a thick fruit jam.
Divide the filling evenly between the part cooked pastry bases.
With the remaining pastry, add a shaped decoration of your choice using a pastry cutter or knife. Stars are great for Christmas! Arrange these pastry tops on top of the fruit filling.
Beat the remaining egg and brush the pastry edges and lids with the egg mixture.
Transfer to the oven to bake for 10-12 minutes until golden brown and the filling is bubbling.