To prepare the pasta e fagioli start by preparing 1/2 liter of vegetable broth that will serve you later.
Meanwhile, with a knife cut the bacon into slices and then cut those slices into thin strips. Then chop the celery, carrots and onion. Take celery, carrots and onion and place them in a blender to get a fine mix of them.
When you've got your chopped vegetables, take a large pan. Pour a little oil and brown a clove of garlic. When it is browned, remove it from the pan and fry the chopped celery, carrots and onion.
Add a ladle of broth to make them simmer the sauce better. Add to the mixture also the butter and, when it is melted, add the bacon.
Add a ladle of broth and stir for cooking the bacon. Now add the tomato paste. Season with salt and pepper.
Then wash the kidney beans and add them to the other ingredients. Stir well to mix all the ingredients and ensure an even cooking. In a separate pot, boil the water and cook the pasta for 8 to 10 minutes.
While the pasta is cooking take three ladles of the sauce and add it to the pasta. Then drain the pasta and add it to the sauce.
Cook the pasta in the sauce. Add finely chopped rosemary and serve your pasta e fagioli when it is still warm.