Wash the tomatoes and remove their skin. The easiest way to do this is to make a shallow incision in the cross shape at the bottom of each tomato and then place it in boiling water. Hold the tomatoes like this for about 1 minute, and then transfer them to a bowl of cold water. Keep them there for 10 seconds, take them out of the water, and then proceed with peeling the skin and cutting them to pieces. You can drain the excess water if tomatoes have released a lot of it.
Dice the onions and the garlic, peel and grate the carrots and parsley root, and cut the red pepper into chunks. Mince the chili peppers.
Pour olive oil into a large pot, add the onions and saute on medium heat for about 10 min. Add garlic, and red horn pepper and saute for a few more minutes. After that, add carrots and parsley roots and continue with the process. If it starts to burn, add some water.
When the vegetables have softened, add tomatoes, chili peppers, and raisins. Cook for 1.5-2 hours on medium heat, stirring occasionally. Make sure the mixture doesn't burn. Towards the end of cooking, add fresh basil leaves and cook for another 5 minutes.
After the mixture has thickened, remove the pot from the heat and blend thoroughly with the immersion blender. Be careful not to burn yourself. After blending, the consistency of the ketchup should resemble a thick sauce. You can further puree the mixture if you want, but I usually don't do that.
Bring the ketchup back to the stove and start adding vinegar and spices. You can add these ingredients gradually and adjust the flavors to your liking.
In the meantime, put the freshly washed jars and bottles to be sterilized at 110°C. You can sterilize jars and bottles in hot water, but personally, I find it more practical to sterilize them in the oven.
Pour the hot ketchup into hot jars through a sterilized metal funnel, being careful not to get ketchup on the edges. Close them very tightly and let them cool completely. As the ketchup cools down, you should hear the typical "pop" sound as the vacuum is being created.
Store the homemade ketchup in a dark, dry, and cool place for up to a year. After opening, ketchup should be kept in the refrigerator and used as soon as possible.