These classic Italian beans are a medium large tan bean, splashed with red/black to magenta streaks. It is very popular in Italian and Portuguese cuisine. They are also known as Cranberry beans in the US. If you can't find Borlotti beans, you can always use pinto beans.
This was a fantastic recipe. I haven't been to Perbacco yet to try Staffan's creations, but I definitely want to now. This soup exceeded high expectations! Instead of Borlotti beans I used the pinto beans as recommended. I also left our the parmesan rind.