In a large stockpot over medium heat, add the olive oil, onion, celery, carrots, and potatoes. Season with salt and pepper and sauté for 5 minutes, and vegetables begin to soften.
Add the minced garlic and cook for 2 minutes. Add the beans, stir, and cook for a couple of minutes.
Add the chicken or vegetable stock and your desired bay leaves, and simmer the soup for 25 minutes. Vegetables should be tender.
While the soup is simmering, make the gremolata. In a small skillet and over low heat, melt the butter and add the panko. Stir the panko every minute or so for evenly toasted panko. Once the panko begins to brown, add the fresh, finely chopped rosemary, minced garlic, red pepper flakes, and sprinkle of lemon zest. Continue stirring until the panko is golden brown. Remove from heat and set aside.
Once the soup has simmered enough that the vegetables are tender, turn the heat off and add all the baby kale and spinach to the pot. Gently stir, and the leaves will wilt but still be bright green.
Divide the soup into bowls and top with the gremolata and a sprinkling of Parmesan cheese. Serve with red pepper flakes for those who might like additional heat!