French Onion Ground Beef Sandwiches in the Crockpot

Transform simple ground beef into a warm, savory French onion sandwich filling using your slow cooker. Thinly sliced sweet onions slow-cook alongside seasoned beef, rich beef broth, and fresh thyme, creating a juicy topping for toasted rolls. It is ideal for busy weeknights, game days, or prepping simple lunches for the week ahead.

Ingredients

• 2 lb 90% lean ground beef
• 2 large yellow onions, thinly sliced
• 3 cloves garlic, minced
• 1 cup low-sodium beef broth
• 2 tbsp Worcestershire sauce
• 1 tbsp fresh thyme leaves
• 1/2 tsp onion powder
• 1/2 tsp black pepper
• 1 tsp salt
• 2 tbsp cornstarch mixed with 2 tbsp water
• 6 slices Swiss or Gruyere cheese
• 6 hoagie rolls, split and toasted

Instructions

1. Place the thinly sliced yellow onions, minced garlic, beef broth, Worcestershire sauce, fresh thyme, onion powder, salt, and black pepper into the slow cooker insert.
2. Crumble the raw ground beef evenly over the onion mixture in small pieces.
3. Cover and cook on LOW for 5 to 6 hours (or HIGH for 2 1/2 to 3 hours) until the beef is fully cooked and reaches an internal temperature of 165 F.
4. Break up any remaining larger chunks of beef with a wooden spoon and stir the ingredients together.
5. Stir in the cornstarch slurry, cover, and cook on HIGH for an additional 15 minutes until the pan sauce thickens.
6. Spoon the warm onion beef mixture onto toasted hoagie rolls, top each with a slice of cheese, and let melt slightly before serving.

Tips

• Using 90% or leaner ground beef keeps the filling rich and juicy without creating excess oil during slow cooking.
• Store the beef filling in meal-prep containers separately from the rolls for up to 4 days in the refrigerator.
• To get a bubbly crust, place assembled open-faced sandwiches under the oven broiler for 2 minutes before serving.