Cook the rice in abundant boiling salted water. When it is slightly underdone, drain it and run it under cold water to stop the cooking process.
While the rice is cooking, prepare the tomato sauce. Pass the contents of the can of tomatoes through a food mill, fitted with the disk with the smallest holes, in order to remove the seeds. Scrape into the bowl any pulp that has stuck to the bottom of the mill.
Put the olive oil and the onion in a saucepan. Set heat to medium and when the onion turns clear add the tomatoes, salt, sugar, pepper, and mint. Cook at a simmer for 15 minutes, stirring from time to time. Do not allow it to boil.
While the tomato sauce is cooking, prepare the stuffing. Grease a skillet with about 1 tbsp olive oil. Add the onion and sauté at medium heat until it turns clear, then add the chopped meats and turn the heat up. Mix it with the onion and break it into small pieces with a wooden spoon. Salt.
When the meat is thoroughly cooked, add about half a cup of tomato sauce. Remove it from the heat and transfer it to a bowl. Mix in the rice. Allow it to cool thoroughly. Then add the chopped hard-boiled eggs, raw eggs, pine nuts, black pepper, and nutmeg. Check the salt.
Prepare the peppers for stuffing. Wash and dry them thoroughly. If using bell peppers, cut off the top in a straight cut as near to the top as possible. If using the long green peppers, cut open the stem end on the diagonal to prevent the stuffing from running out when they are lying down in the pan. In either case, remove the seeds and the "ribs" as best as possible. Rub each pepper with olive oil inside and out.
Stuff the peppers loosely. Place about 1 tbsp of tomato sauce on top and bake at 350° for 30 to 40 minutes. These peppers may be served hot or cold.