Remove the pineapple from the tin, and pour the juice into a small bowl for later.  

Chop the pineapple into small pieces (as small as you can). 

Carefully scoop the pineapple into a sieve with a bowl underneath. 

Use a spatula or spoon to crush them a little, forcing juice into the sieve. 

Pour this juice into the bowl with the rest. 

Preheat the oven to 180 degrees C and prepare a 2-pound loaf tin. 

In a large mixing bowl, whisk together the margarine and caster sugar. 

Whisk in the eggs, one at a time. 

Add the flour and whisk until the mixture is smooth. 

Fold in the pineapple pieces until they are evenly distributed. 

Tip the cake mix into the prepared tin.

Bake for 45-50 minutes until the sponge is cooked (use a skewer to test). 

While the cake is still warm in the tin, stab it all over with a skewer, stabbing right to the bottom. 

Place the sugar for the syrup in a small saucepan. 

Add most of the pineapple juice, retaining two tablespoons for the drizzle. 

Warm over low heat, stirring until the sugar has dissolved. Don’t let it simmer. 

Remove from the heat and pour liberally over the cake, directing it toward the holes. 

Leave in the tin to cool completely. 

Once cool, carefully remove from the tin. 

Place the icing sugar in a small bowl and add the remaining pineapple juice.