Sift the flour, cocoa, baking soda, salt and spices in a bowl. Set aside.
Combine the oil, molasses, juice and sugar in a small saucepan. Set it on low heat and stir till the sugar has dissolved. Set aside to cool for a few minutes.
Meanwhile preheat the oven to 160 C. Grease a 9x5 loaf tin with oil or line it with greased baking paper for easy removal.
In a mixing bowl, pour the cooled molasses mixture and add in the eggs, vanilla and milk. Whisk well to combine.
Fold in the flour mixture gradually into the liquid until incorporated. A few lumps are ok.
Pour the batter into the prepared tin, smoothen the top and bake for 35 to 40 minutes until a toothpick inserted into the center comes out clean. You may need to bake an additional 5 to 10 minutes, so if the top is darkening quickly, cover the tin loosely with foil and continue baking.
Allow the cake to cool in the tin for 15 minutes, then remove and place on a wire rack to cool completely before slicing. Store in an airtight tin for about 2 to 3 days at room temperature, or refrigerate for a week. Happy baking!