Heat 2 tablespoons of extra-virgin olive in medium sauce pan over medium-low heat, add the onion and cook until it begins to turn golden, adding a bit of warm water if necessary.
Add the borlotti beans, sage and rosemary leaves, pour in half the stock and simmer for 10 minutes, stirring occasionally, then season with ½ teaspoon (or to taste) of fine sea salt.
Remove half of the bean soup mixture, transfer into a blender, blend it until smooth and return it into the pot. Pour the remaining stock into the pot, add in the pasta and cook, stirring occasionally, until the pasta is cooked through.
Divide the pasta e fagioli among bowls, top with fresh parsley, optional Parmesan cheese and freshly-cracked black pepper, drizzle with the remaining extra-virgin olive oil and serve.
STORAGE:Store leftovers in an airtight container and refrigerate up to 2 days. You can then reheat on the stove over low heat, until nicely warm.