Start by chopping the carrots into thick chunks and dicing the onion. Set them aside on your cutting board. Open the can of tomatoes and rinse the green beans if using fresh. Measure out the broth and herbs so everything is ready for easy assembly.
Heat a large skillet over medium heat and add a splash of olive oil. Once shimmering, add the diced onions and sauté until they turn translucent and smell sweet, about 5 minutes. This builds a rich base for the soup.
Transfer the sautéed onions to the crockpot. Add the thick-cut carrots, canned tomatoes with their juice, vegetable broth, and dried thyme. Stir everything together well, ensuring the vegetables are evenly distributed in the broth.
Set the crockpot to low heat and cook uncovered for about 6 to 8 hours. During this time, the vegetables will soften, and the flavors will meld into a fragrant, cozy broth. The house will fill with a warm, inviting aroma.
About halfway through, roughly 3 to 4 hours in, add the green beans. Stir gently to incorporate. This keeps them fresh and slightly crisp, adding texture to the finished soup.
Check the soup near the 6-hour mark. The carrots should be tender when pierced with a fork, and the broth should be thickened slightly, fragrant, and bubbling gently. Taste and season with salt and pepper as needed.
Once ready, turn off the crockpot. Remove the bay leaf, if used, and stir in a splash of olive oil for added richness and shine. Chop fresh parsley and sprinkle over the top for a burst of fresh herbal aroma.
Ladle the warm soup into bowls, ensuring each serving has a good mix of vegetables and broth. Drizzle with a little more olive oil if desired, and serve with crusty bread for a complete comforting meal.
