1 tbsp vegetable oil
1 median onion chopped
8 cloves garlic, minced
3 14oz cans diced tomatoes
6 cups chicken broth
6 cups fresh basil leaves
1 tbsp lemon juice per jar

saute onions in oil till clear, add garlic and saute 30 seconds, add tomatoes and broth. Bring to boil.
reduce heat to low, add sliced basil and simmer a few minutes.
Puree soup with blender or hand mixer.
Add 1 tbsp Lemon juice to jar, fill with soup to 1/2 inch head space, place in bath. Process for 30 mins.

It is untested so both the density and the pH is unknown and the processing time is just a guess.

It is a do at your own risk recipe.

Dave

Besides, assuming the chicken broth is canned, you're canning canned tomatoes and canned broth amended with a few other ingredients, all available year-round except for the fresh basil. And that can be frozen in the summer. In other words, you'd essentially be re-canning, a total waste of your jars, lids and utilities.

Carol