Chop onion. Heat oil over medium-low heat in a large saucepan and add onion. Cook and stir while you continue.
Slice carrot on a diagonal into 1/4-inch-thick pieces and add to saucepan. Cook and stir another 2 to 3 minutes.
Mince garlic, stir into vegetables, and cook another minute.
Add broth, tomato paste, rosemary, thyme, salt, pepper, red pepper flakes, and bay leaves. Bring to a gentle boil, then reduce heat to keep at a simmer uncovered about 5 minutes.
Add beans and cook another 5 minutes.
While soup simmers, remove kale leaves from the center stem. Chop into small pieces to yield 4 to 6 cups, lightly packed. Place in a colander and rinse well. (If using frozen kale, thaw in the microwave now.)
Use the back of a spoon and mash some of the beans to create a thicker broth. Add kale. Cover and simmer 15 minutes.
Add tomatoes and simmer uncovered another 15 to 30 minutes, or longer.
Remove from heat and stir in Parmesan cheese and juice of half the lemon. Remove bay leaves then adjust seasonings, to taste. Add more lemon juice, if desired.
Sprinkle additional grated Parmesan on top of each individual serving.