Hash Brown Casserole

Name: Hash Brown Casserole
Ingredients: 1 package (32 ounces) frozen hash browns (thawed); 6 slices bacon (cooked to a crisp, drained and crumbled (reserve some crumbles for garnish)); 1 yellow onion (grated); 1½ cups crumbled feta cheese; 1½ cups shredded mild cheddar cheese; 1½ cups nonfat plain yogurt; 2 tablespoons butter (softened); ½ cup all purpose flour; 1 teaspoon dried rosemary; 1 teaspoon dried thyme; salt and freshly ground black pepper (to taste); 1 large egg (lightly beaten); chopped green onions and crumbled bacon (for garnish (optional))