In a large sauce pan heat the olive oil and onion over low.
Sweat the onion for 5 minutes.
Then add in the garlic, and sweat for 1 minute more.
Turn the heat up to medium and add in the lemon juice and stir.
Next add in the eggplant, broth and 1/2 teaspoon salt and bring to a simmer. Simmer for 5 minutes.
Then add in the tomatoes, zucchini, white beans and oregano, and simmer for 5 more minutes. Add in the basil and parsley. Remove from the heat and stir until the herbs are bright green.
Serve warm, and with grated Parmigiano-Reggiano on top if desired.