To begin, soak raisins in warm water or rum for 15 minutes. This softens them and infuses extra flavour. Drain well before adding to the dough. Transition to mixing the batter.
In a large bowl, combine flour, baking powder, salt, and sugar. Whisk lightly to distribute the leavening and sweetness evenly. Move to blending wet ingredients.
In a separate bowl, beat the egg with yoghurt, rakija (or rum), and citrus zest. Whisk until smooth and aromatic. Transition to combining wet and dry mixtures.
Gradually fold the wet mixture into the flour blend. Stir until a sticky dough forms, then gently mix in the raisins. Avoid over mixing to keep fritule light. Transition to preparing oil for frying.
Pour vegetable oil into a deep pan, enough to cover the fritule as they fry. Heat over medium until it reaches around 170°C. Test by dropping in a small bit of dough, it should rise slowly and bubble. Move to frying.
Using a teaspoon or small scoop, carefully drop portions of dough into the hot oil. Fry in batches for 3–4 minutes, turning occasionally until golden brown and puffed. Transition to draining.
Remove fritule with a slotted spoon and place them on kitchen paper to drain excess oil. Allow to cool slightly before dusting. Prepare for serving next.
Arrange fritule on a platter and dust generously with icing sugar. Best enjoyed warm with coffee, dessert wine, or simply as a festive snack.