Preheat your oven to 180C / 350F / Gas mark 4 and lightly grease a 2-pound loaf tin or use a liner like I did.
In a medium-sized mixing bowl add the flour, sugar, spices, baking soda and salt and give it a gentle mix so everything is well combined.
In a small saucepan over a low heat add in the butter and molasses / black treacle and very gently heat until the butter is melted into the molasses.
Give it a few minutes to cool down a little bit and whisk in the lightly beaten eggs and half of the milk.
Pour this mixture into the dry ingredients. Then carefully mix it all together to form a light in colour pourable batter. You may need to add more of the milk at this time to loosen the batter. You want it pourable but not overly runny, I found I did not use all of the milk.
Fold in your cranberries.
Pour the batter into your prepared tin and pop it into your hot oven.
I have a notoriously slow oven so it took 50 minutes to bake through but check it at the 35-minute mark to see if it's done. Insert a pick and it should come out clean.
Once baked through take it out of the oven but leave it in its tin to cool for 10 minutes then transfer it to a wire rack to fully cool down.
For the glaze, mix the icing sugar with the juice from half an orange and drizzle over the top of your cool loaf.
Slice and enjoy.
I have found this loaf freezes well for at least 2 months unglazed.