1. Heat the olive and garlic together over medium heat in a Dutch oven or large pot.
2. Stir the garlic and olive oil, cooking the garlic, just until the garlic softens, about 1 minute. Add the escarole in batches, stirring in the garlic so it’s not all at the bottom of the pot, where it can burn (and get bitter). Once all the escarole is added, stir in the salt and some freshly ground black pepper. Lower the heat, cover the pot, and let the escarole cook, lifting the lid once or twice while it’s cooking, until the escarole is completely wilted, 2-3 minutes.
3. Remove the lid and pour in the stock. Bring the mixture to steady simmer. Stir in the cooked beans, then drop in the meatballs. (Don’t stir them, though, which can cause them to lose their shape; just place them in the soup.) Cover the pot and simmer until the meatballs are cooked through, 3 to 5 minutes, depending on their size.
4. Ladle the soup into bowls and top with shavings of Parmesan and perhaps an extra drizzle of olive oil, if you’d like.