Though shells for this type of stuffed food are made from a variety of ingredients, the stuffing for all is more or less the same. Here is how to prepare it.
Heat oil in a big skillet and cook ground/minced meat, stirring occasionally, and breaking down any lumps with the back of a spoon. When moisture evaporates, add onion and stir until transparent, 10 to 15 minutes, total.
Add the rest of the ingredients in the last 5 minutes of cooking, and stir gently. Set aside to cool down.