Start by rinsing the dried white beans thoroughly in cold water, removing any debris or shriveled beans. If soaking overnight, drain and set aside; for a quick soak, bring the beans to a boil in water for 2 minutes, then let sit covered for an hour. Drain and rinse after soaking.
Chop the onion into small dice and mince the garlic cloves. Chop the carrots into small, even pieces to ensure they cook through during the slow simmer.
Add the soaked beans to the slow cooker, along with the chopped onion, minced garlic, chopped carrots, fresh thyme sprig, bay leaf, and vegetable broth. Stir everything together to combine.
Cover the slow cooker with the lid and cook on low for about 8 hours, or until the beans are tender and the soup has thickened to a velvety consistency. During cooking, the beans will soften and absorb the aromatic flavors, filling the house with a fragrant aroma.
Once cooked, remove the bay leaf and thyme sprig. If you prefer a creamier texture, use an immersion blender to blend part of the soup directly in the slow cooker until smooth, or mash some beans with a fork for added creaminess.
Taste the soup and season generously with salt and pepper, adjusting to your preference. If the soup is too thick, stir in a splash of hot broth or water to loosen it up.
Finish by drizzling a tablespoon of olive oil over the soup for added richness and shine. Let the soup sit for a few minutes to settle the flavors, then ladle into bowls and enjoy the comforting, velvety texture.
