Eggplant with Lentils and Goat Cheese

Name: Eggplant with Lentils and Goat Cheese
Ingredients: 2 globe eggplants (1 pound each), halved lengthwise; Vegetable oil cooking spray; 3/4 teaspoon kosher salt, divided; 1 tablespoon olive oil; 1 medium onion, finely chopped; 2 diced celery stalks; 1 large carrot, peeled and diced; 2 cloves garlic, finely chopped; 2 cups packaged steamed lentils (such as Melissa's); 1/2 cup low-sodium vegetable broth; 2 tablespoons balsamic vinegar; 1/4 teaspoon freshly ground black pepper; 1/4 cup chopped fresh mint, plus torn leaves for serving; 2 ounces crumbled goat cheese