Preheat oven to 300F; line an 8-inch square cake pan with foil and set aside.
Put sugar, butter and fruits (with juice from tinned pineapple) in a saucepan over medium to medium-low heat; note that all currants or all raisins can be used instead of both; stir often until the butter melts, then remove from heat.
Note that you could also do that in a microwave oven.
Beat eggs with a whisk until frothy in a small bowl; slowly whisk eggs into fruit mixture.
Combine all dry ingredients together then add all at once to wet mixture; stir well.
Pour into prepared pan and bake for 1-1/2- 2 hours, or until a wooden toothpick inserted in centre comes out clean.
When cool enough to handle, remove from pan and store in an airtight container.