Add the water, salt, treacle, butter & starter to your bowl and mix well.
Add the flour and bicarbonate of soda and mix to combine.
Knead the dough for around 5 minutes.
Wrap up and refrigerate for 30 minutes.
Roll the dough to size, place it on the paper and in the tray.
Score it at this point.
Cover and rest in fridge for 30 minutes.
During this time pre-heat your oven to 180C (360F) with the fan on.
Prick the dough with a fork all over and brush with the egg.
Sprinkle on the toppings and press them in lightly.
Bake for around 20 minutes.
Cool down and enjoy or store for later.
