Preheat oven to 230C (about 446F) mov ethe oven rack so it is positioned near the top of the oven.
Sift the flour, salt, baking soda, cream of tartar, cinnamon, and mixed spice into a large bowl. Rub in butter until the mixture resembles bread crumbs.
In a small saucepan, gently heat the milk and stir in the sugar and treacle until dissolved. Remove from heat and pour into the dry ingredients. Stir until it turns into a soft dough.
Turn the dough out onto a floured surface and knead lighly until smooth.
Bake for 12-15 minutes until the bottoms are lightly browned.
Cool on a wire tray, and serve split (do not cut, simply pull apart gently). Serve with butter or cream cheese.