Cut fresh tomatoes into eighths, cut the onion, carrots and celery into small cubes. Leave the bacon in the pan. When the bacon is lightly seared, add the minced meat and fry. As soon as the meat is seared all over and has turned a nice brown color, add the onions, carrots and celery to the pot. When the vegetables start to water, add fresh tomato wedges. Mix everything, fry briefly and deglaze with red wine. Add canned tomatoes and 1 - 2 sprigs of rosemary (or alternatively oregano or thyme).
Now the Bolognese has to simmer for 2 to 3 hours. Only now season to taste with salt and pepper. Finally, cut the cold butter into pieces and add to the Bolognese.
Bolognese goes well with spaghetti.
Tip: if there is Bolognese left on the next day, it can be used to make a lasagna.