In the bowl of an electric mixer, bring together 50 grams of flour, yeast, half the sugar, and water.
Stir the ingredients and mix until smooth.
Cover with a plastic wrap and leave to rest in a warm place until the mixture is foamy (about an hour).
Add the milk, egg yolks, vanilla and salt to the mixture and use a dough hook on low speed to incorporate the ingredients.
Slowly add the rest of the flour a few tablespoons at a time.
Add the oil and mix for another 4-5 minutes until the dough is smooth.
Cover with plastic wrap and refrigerate overnight.
When ready to cook, transfer the dough to a lightly floured surface, and let it warm up a little before rolling it out, about 15 minutes.
Roll out the dough to half-inch thickness and cut out rounds with a 1.5-inch diameter cutter.
Pat any leftover dough into a rectangle and cut more circles out of it.
Heat the oil in a deep-fryer or heavy-bottomed saucepan to 350F/180C.
Deep-fry, without crowding the pan, turning each disc once or twice for even browning, until puffed and golden.
Drain on paper towels and roll in sugar before serving with lemon curd on the side or melted chocolate.. yum!