Warm the olive oil in the Dutch oven over medium heat for 1 minute, until it shimmers. Add the onion, carrots, and celery. Cook for 8 minutes, stirring every minute or two, until the onion turns translucent and the carrots look glossy. Keep the heat at medium so the vegetables soften without browning.

Stir in the garlic, tomato paste, and thyme. Cook for 2 minutes, stirring constantly, until the paste darkens from bright red to brick red and the pot smells sweet and toasty. Scrape the bottom as you stir.

Add the cabbage in two big handfuls, stirring after each one. Cook for 5 minutes, until the pile wilts to about half its height and the edges of the leaves turn glossy.

Pour in the broth, water, and diced tomatoes with their juices, then drop in the bay leaf. Turn the heat to high and bring to a boil, about 6 minutes, until large bubbles break across the whole surface.

Lower the heat to medium-low and stir in the beans. Simmer, partly covered, for 15 to 18 minutes at a gentle simmer around 200°F, with small bubbles at the edges, until a piece of cabbage tears easily against the side of the pot but still holds its shape.

Turn off the heat, remove the bay leaf, and stir in the lemon juice. Season with kosher salt and pepper a pinch at a time, tasting after each, until the broth looks deep red-orange and tastes bright and savory.

Ladle into bowls and top with parsley. If you can wait, let the pot stand 5 minutes first, until the steam thins and the broth thickens slightly.