In a bowl, mix the dry yeast with 375 ml of lukewarm water (about 37°C / 98°F). Mix the flour with salt, then add the yeast mixture and knead until a smooth dough forms. Cover and let rise for 30 minutes.
Peel and slice the onions. Heat oil in a pan over medium heat and cook the onions, stirring occasionally, for 10-15 minutes until golden brown. Add the diced bacon and cook for 3-5 minutes until browned. Remove from heat and let cool completely. Add the cooled onion and bacon mixture to the dough and knead vigorously. Cover and let rise for another 30 minutes.
With wet hands, shape the dough into small rolls. Place them on a baking tray lined with baking paper. Bake in a preheated oven at 200°C (390°F) with top and bottom heat for 30 minutes until the rolls are golden brown.