Dissolve the yeast in a little water.
Add 1/4 cup flour and form a paste.
Cover the mixture with a cloth and let it rise for at least an hour.
Pour the rest of the flour onto a rolling board and prepare a pastry with the eggs, 1/4 teaspoon of sugar, 4 spoonfuls of milk, a pinch of salt and the yeast mixture above.
Knead the pastry well and when done place in a classic Rum Babà shaped dish lined with butter.
Cover with a dishcloth and again let the pastry rise for another hour.
In a pan melt half a gram of sugar in half a cup of water.
Remove from the heat before it starts to change color and pour in a glass of rum and lemon juice.
Pour this heady brew onto the Rum Babà.
Serve cold.