In a bowl, mix together all of your dry ingredients.
Cut your butter in rough slices about 1/8 inch thick and add them to the flour mixture. Stir a few times to coat the butter, then add your cold water and stir again just until you get a very rough dough that you can form into a ball. (Alternatively you can use a food processor for this, just be careful not to over-mix if doing it this way).
Wrap the rough dough ball and place it in the fridge for 30min to chill.
Next on a coconut floured surface OR between two pieces of greased parchment paper roll the dough out into a rectangle as best you can (it’s okay if it’s a bit rough the first time, just gently push in the edges if pieces separate – also see my tips on rolling the dough if it’s dry or sticking).
Fold one side of the rectangle inward, then the other until the dough looks like this (see photo).
Turn the dough 90* and Roll the dough out into a rectangle again, pushing down the layers you just formed. Repeat this 4-5 times. As you go, the dough will begin to form a nicer looking rectangle and the butter will become streaky and less clumpy.
Fold once more and then wrap your dough and place it in the fridge to cool for another 30min.
While your pastry dough is chilling you can make your filling by placing your ground sausage in a bowl with all of the filling ingredients and using a spoon or your hands to mix everything together. Set aside.
When your dough has finished chilling, pre-heat your oven to 400*F and then roll out your dough into a rough rectangle (doesn't have to be perfect) and cut that rectangle into 4 pieces. Roll out each piece as best as you can into a rectangle shape (see photos). You can also cut the edges with a knife or pizza cutter to make it look more even.
Next add filling down the middle of each rectangle (I like to have my filling just slightly closer to one side than the other because it makes it easier to roll later).
Roll them up like you would a cinnamon roll making sure that no filling is sticking out except at the sides. Pinch the long edge together to make sure these don't roll apart in the oven (because trust me they will if you don't pinch them well! You can also be careful to roll your dough thinner to prevent this issue).
Next cut each log into 4 pieces. Make 3 tiny pokes with a knife into the top of each piece. Then place them on a parchment lined baking sheet.
Mix your reserved whisked egg from earlier with 1/2 tbsp water and brush each keto sausage roll generously with the mixture.
Bake the sausage rolls for 20-25min or until puff pastry is golden brown and crispy. Enjoy your Keto Sausage Rolls warm with mustard or sugar free syrup...or my personal favourite, Keto Plum Sauce.