This Slider Casserole is packed with crave-worthy cheeseburger vibes. Feed a crowd or enjoy for a weeknight meal. The leftovers will be in high demand.
Heat a large skillet over medium heat. Add the ground beef and onions. Cook until beef is no longer pink, crumbling the meat as it cooks. Drain the excess fat.
To the browned meat, add the ketchup, mustard, Worcestershire sauce, salt, and pepper. Stir to combine. Simmer for 2-3 minutes.
Meanwhile, in a small saucepan, melt the butter and stir in the parsley and dried onion and garlic.
In a 9x13 casserole dish, arrange the bottom of the slider buns. Brush with some of the butter mixture. Top with Cheddar cheese. Spread the beef mixture evenly over the buns and cheese. Top with American cheese. Arrange the pickle slices evenly over the sliders.
Brush the inside of the top buns with some of the butter. Arrange the buns on top of the sliders. Brush the top with the remaining butter.
Cover the dish with aluminum foil. Bake for 20-30 minutes until cheese is melted and sliders are warm throughout. Serve.
Notes
Store the sliders in an airtight container or wrap the casserole dish tightly with plastic wrap. These burgers will keep for 3-4 days.
To reheat: Wrap 1-2 sliders in a paper towel and microwave until warmed through. This method prevents the buns from drying out.
To make-ahead, assemble the casserole up to 1 day in advance. Wait to brush the butter mixture over the top of the rolls until ready to bake.
The meat mixture can be made 2-3 days in advance. When ready to serve, assemble the casserole and bake according to the recipe directions.