Step 1: In a large Dutch oven or heavy-bottomed pot, heat the olive oil over medium heat. Add the chopped onion and sauté until softened and translucent, about 5-7 minutes.
Step 2: Add the minced garlic, dried thyme/oregano (if using), and red pepper flakes (if using). Sauté for another minute until fragrant, being careful not to burn the garlic.
Step 3: Pour in the vegetable broth, add the rinsed white beans, and the bay leaf. Bring the mixture to a gentle simmer.
Step 4: Reduce the heat to low, cover the pot, and let it braise for 20-30 minutes, stirring occasionally, until the beans are tender and have absorbed some of the liquid.
Step 5: Stir in the chopped seasonal greens. If using tougher greens like kale, add them first and allow them to wilt down for a few minutes before adding more tender greens like spinach. Cover the pot again and continue to cook for another 5-10 minutes, or until the greens are tender but still vibrant.
Step 6: Remove the bay leaf. Stir in the fresh lemon juice. Season generously with salt and freshly ground black pepper to taste. Drizzle with a little extra virgin olive oil before serving, if desired.