Vegetarian Matzo Ball Soup With Caramelized Cabbage

Name: Vegetarian Matzo Ball Soup With Caramelized Cabbage
Ingredients: 4 large eggs, beaten to blend; ½ cup extra-virgin olive oil, divided, plus more for serving; ¼ cup finely chopped chives, plus more for serving; 2½ tsp. Diamond Crystal or 1½ tsp. Morton kosher salt, divided, plus more; 2½ tsp. freshly ground black pepper, divided, plus more; 1 cup (120 g) matzo meal; 1 small savoy or green cabbage (about 2 lb.), thinly sliced; 1 medium onion, thinly sliced; 4 garlic cloves, crushed; 2 large leeks (about 1 lb.), white and pale green parts only, thinly sliced; 8 oz. peanut or other very small potatoes, halved; ½ cup (packed) coarsely chopped parsley, plus more for serving; 1–2 tsp. fresh lemon juice