Mix the warm milk, yeast and sugar in a stand mixer bowl and let it rest for 5 minutes.
Add the flour and salt and knead slowly. Add the eggs, one by one. Increase the speed to medium and slowly add the butter (one small cube at a time and wait until it combines with the dough. This will take about 10 minutes. The dough will be very sticky and that's okay, don't be tempted to add flour).
Place the dough in a large greased bowl using a rolling pin. Cover with plastic wrap or a towel and let rise for 90 minutes.
Sprinkle flour on your working surface and place the dough on top (you can use some flour to release it from the bowl if necessary). Divide the dough in half and transfer each part to a round greased baking pan. Shape each dough part into a thick circle and let rise for 30 minutes.
Preheat the oven to 355 °F (180 °C) and bake for 16-17 minutes, or until golden.
In the meantime, combine the oil and sugar for the brushing in a small bowl. When the cakes are ready, gently brush them with the mixture, then let them cool off for 15 minutes.
Place one cake on a plate with the flat part facing up. Spread the jam and save a teaspoon for later. Place the other cake with the flat part on top of the jam layer. Sprinkle powdered sugar and pour the teaspoon of jam on top. Serve warm.