Cheesy Dream Lasagna Casserole: Unlayered Comfort!

Ingredients

• 1 tablespoon olive oil
• 1 pound ground beef
• 1 medium yellow onion, chopped
• 2 cloves garlic, minced
• 1 (28-ounce) can crushed tomatoes
• 1 (15-ounce) can tomato sauce
• 1 teaspoon dried oregano
• 1/2 teaspoon dried basil
• 1/4 teaspoon red pepper flakes (optional)
• Salt and freshly ground black pepper to taste
• 1/2 cup beef broth
• 1 pound lasagna noodles, broken into 2-inch pieces
• 15 ounces ricotta cheese, full-fat or part-skim
• 1 large egg, lightly beaten
• 1/4 cup grated Parmesan cheese, plus more for topping
• 1/4 cup chopped fresh parsley (optional)
• 2 cups shredded mozzarella cheese
• Salt and pepper to taste