Step 1

For food safety reasons, you will need to boil the dried cannellini beans for 10 minutes before prepping the soup. Place the dried beans in a colander and rinse well. Transfer to a medium saucepan and cover with several inches of water. Place over high heat and bring to a boil. Cook the beans, stirring once or twice, for at least 10 minutes. This boil time helps to deactivate the naturally occurring toxin, Phytohaemagglutini, that can occur in some variety of dried beans. Drain the beans in a colander and proceed with the rest of the recipe.

Step 2

If you own a stovetop-safe slow cooker insert (alternatively, you can do this in a normal saucepan or skillet and transfer it to the slow cooker): Heat the insert over medium heat. Add the diced bacon and cook, stirring frequently, until the bacon is crispy and most of the fat has rendered. Using a slotted spoon, transfer the bacon, leaving the rendered fat behind, to a small bowl.

Step 3

Add the sliced leeks to the pot and reduce the heat to medium-low. Sauté the leeks, stirring occasionally, until they are just beginning to soften, about 3 to 4 minutes. Add the diced celery, dried bay leaves, and fresh rosemary sprig, and sauté for an additional 5 to 6 minutes, stirring occasionally.

Step 4

Transfer the insert to the slow cooker base. Add the cooked bacon, boiled and drained cannellini beans, and chicken broth. Stir together. Cook on high heat for 5 to 6 hours, or until the cannellini beans are cooked, tender, and very fragrant. Remove the dried bay leaves and any tough rosemary stalks, if present.

Step 5

Transfer one large ladleful of soup (roughly 1 cup) to a small food processor blender and puree until mostly smooth. Transfer the pureed soup back into the slow cooker with the remaining soup and stir. Serve hot with a glug of high-quality extra virgin olive oil and a sprinkling of fresh chopped rosemary.