In a little bowl start mixing the yeast with 2 lukewarm tablespoons of water. Add 50g of flour and mix, leave it to rise for 30 min.
Prepare the rest of the ingredients.
Put the mixture in a mixing bowl with the soy milk, eggs, flour, margarine, 1 teaspoon of sugar, a pinch of salt.
Now use your hands to knead the dough: push the dough out in one direction with the heel of your hand, then fold it back on itself. Turn the dough by 90 degrees and repeat. Kneading in this way stretches the gluten and makes the dough elastic. Do this for about 15 minutes until the dough is smooth and stretchy.
Cover with a damp tea towel or cling film and set it aside to prove for 45 min.
Once the dough has doubled in size, scrape it out of the bowl to shape it and set it aside to prove for another hour and half.
Pre-heat your oven to the 200°C.
Bake for 30 mins.
While it is baking, prepare the syrup. Put water and sugar into the saucepan.
Medium heat until it reaches a light brown colour (7-8 min).
Let it cool for 10 min before adding the rum.
Remove the cake from the mould.
Transfer to a recipient larger than the cake.
Pour the syrup on the cake, it should absorb all of it.