Step 1: Preheat the Oven
Preheat your oven to 350°F (175°C). Grease a 9×13-inch baking dish with butter and set aside.
Step 2: Cook the Onions
In a large skillet, melt the butter with the olive oil over medium heat. Add the sliced onions and cook, stirring occasionally, until they are soft and caramelized, about 20-25 minutes. The onions should be golden brown and have a deep flavor. Season with a little salt and set aside.
Step 3: Cook the Ground Beef
In the same skillet, add the ground beef and cook over medium-high heat, breaking it up with a spoon as it cooks. Once the beef is browned, drain any excess fat. Stir in the Worcestershire sauce, Dijon mustard, garlic powder, onion powder, and a pinch of salt and pepper. Cook for another 2-3 minutes to blend the flavors, then remove from heat.
Step 4: Assemble the Casserole
Layer half of the cubed rye bread at the bottom of the greased baking dish. Top the bread with half of the caramelized onions, then half of the cooked ground beef. Sprinkle 1 cup of shredded cheese evenly over the beef. Repeat the layers: the remaining bread, onions, beef, and another 1 cup of cheese.
Step 5: Prepare the Egg Mixture
In a medium mixing bowl, whisk together the beef broth, milk, eggs, and mayonnaise (if using). Season with a pinch of salt and pepper. Pour the egg mixture evenly over the casserole, making sure it soaks through the layers.
Step 6: Bake the Casserole
Cover the casserole with foil and bake in the preheated oven for 30 minutes. After 30 minutes, remove the foil and bake for an additional 10-15 minutes, or until the cheese is melted and bubbly, and the top is golden brown.
Step 7: Let It Rest and Serve
Once the casserole is done baking, let it rest for 5-10 minutes before serving. This will help the flavors meld and make it easier to slice.
Why This Patty Melt Casserole Is the Perfect Comfort Food:
This casserole has everything you love about a traditional patty melt, but in an easier, shareable form. The buttery rye bread soaks up the rich flavors of the beef and onions, while the Swiss cheese melts into gooey perfection. It’s an incredibly satisfying dish that’s perfect for weeknight dinners, game day gatherings, or any time you need a hearty meal that feeds a crowd.
Tips for the Best Patty Melt Casserole:
- Bread Options: While rye is classic for a patty melt, you can substitute with sourdough, white bread, or even a French baguette for a different texture and flavor.
- Cheese Variations: Swiss cheese adds a nice sharpness to the dish, but feel free to mix in cheddar, mozzarella, or provolone for a cheesier casserole.
- Add Some Heat: If you want to spice things up, add a few dashes of hot sauce to the ground beef or sprinkle some red pepper flakes into the egg mixture.
Serving Suggestions:
Pair this casserole with a crisp green salad or some roasted vegetables for a complete meal. You could also serve it with a side of oven-baked fries or a creamy coleslaw to mimic the classic diner experience.
Conclusion:
This Patty Melt Casserole is the ultimate comfort food, combining all the flavors of the beloved sandwich into one easy-to-make dish. Whether you’re making it for a family dinner or bringing it to a potluck, it’s sure to be a crowd-pleaser. The combination of juicy beef, sweet caramelized onions, and melted cheese all soaked into crispy bread makes each bite satisfying and delicious. Try it once, and it might just become your new favorite casserole!