First, roughly chop the onion and smash the garlic. Heat a soup pot on medium heat and put in the olive oil, onion and garlic. Cook together for 5-10 minutes, until the onion begins to look transparent. Now add the beans, chicken broth, sage leaves, pepper flakes and salt and pepper. Reduce the heat to medium-low and simmer with the lid on for 20 minutes. Then, either with an emersion blender or a regular blender, puree the soup until smooth. Taste for additional salt and pepper.
The soup tastes great alone, but I added these croutons on top and it was delicious.
Preheat the over to 350 degrees. In a bowl, add olive oil, garlic powder, salt, pepper and parsley. Then add the bread and mix until the cubes are lightly coated. Put on a baking sheet and cook for 5 minutes, then stir and flip them, and cook for 5 to 10 more minutes, until they are golden brown.
To serve, top the soup with croutons and some Parmesan cheese.