Rinse the dried white beans thoroughly under cold water, picking out any debris. Set aside to drain.
Chop the onion into rough pieces and mince the garlic cloves. Heat a tablespoon of olive oil in a skillet over medium heat and sauté the onion and garlic until fragrant and translucent, about 3-4 minutes. This deepens their aroma and begins building a flavorful base.
Add the sautéed onion and garlic to the slow cooker. Pour in the vegetable broth, then stir in the diced carrots and the sprig of fresh thyme or dried herbs. Give everything a good stir to combine.
Stir in the rinsed beans, ensuring they are submerged in the broth. Cover the slow cooker and cook on low for 8 to 10 hours, or on high for 4 to 6 hours, until the beans are tender and slightly breaking apart.
About 30 minutes before serving, check the soup. If it’s too thick, add a splash of hot broth or water. For a creamier texture, mash some beans directly in the pot with a spoon or use an immersion blender to blend part of the soup until silky.
Remove the herb sprig if used. Taste the soup and adjust seasoning with salt and freshly cracked pepper. Drizzle with a little olive oil to add richness and finish with fresh herbs if desired.
Serve the soup hot, ideally with crusty bread on the side. Enjoy the cozy, velvety texture and comforting aroma of this simple, hearty dish.
