Ratatouille with Roasted Potatoes

Name: Ratatouille with Roasted Potatoes
Ingredients: 4 large potatoes; 1 can (28 ounces whole peeled tomatoes); 2 tbsp tomato paste; 6 tablespoons extra-virgin olive oil; 1 large eggplant (1 pound, cut into 1-inch pieces); Coarse salt and ground pepper; 2 large yellow onions (1 pound total, diced large); 1 head garlic (cloves smashed and peeled); 2 bell peppers (any color, seeded and diced large); 2 large zucchini (1 pound total, diced large); 1/2 cup eston lentils; 1 bay leaf; 1 tablespoon fresh marjoram or oregano leaves; 2 to 3 tablespoons red-wine vinegar; 1 cup greek yogurt