Grits and Greens Casserole

Name: Grits and Greens Casserole
Ingredients: 4 slices bacon, chopped (optional); 2 teaspoons extra-virgin olive oil; 1 small onion, diced; 4 garlic cloves, minced; 2 cups reduced-sodium chicken broth or 2 cups vegetable broth, divided; 1⁄4 teaspoon salt; 16 cups chopped collard greens (about 1 large bunch, 1 1/2-2 pounds) or 16 cups kale, stems removed (about 1 large bunch, 1 1/2-2 pounds); 2 cups water, plus more as needed; 1 cup grits (not instant); 3⁄4 cup shredded extra-sharp cheddar cheese, divided; 1⁄4 cup prepared salsa; 1 large egg, lightly beaten