These warm and gooey ham and cheese sliders are a dinner time home run! Perfect for using up leftover ham, these sandwiches can be made ahead for a casual dinner or for a crowd.
Add 3 tablespoons butter to a large non-stick skillet set over medium heat. Add the onions and cook until soft and lightly golden brown, about 20 minutes.
Meanwhile, preheat the oven to 375 degrees.
Spread the inside of the rolls with mustard. Layer the bottom half of the buns in the baking dish. Top with the onions.
Layer half of the cheese followed by the ham and the remaining cheese. Replace the top of the buns.
In a small pan, melt the remaining 4 tablespoons of butter. Stir in the parsley, minced onion, and minced garlic.
Brush the butter mixture over the top of the buns. Cover with foil and bake for 30 minutes until warmed through.
To reheat, wrap one or two sliders in a damp paper towel and microwave for 40-55 seconds until warm. Time will vary depending on the wattage of the microwave.
Notes
To make ahead: Assemble the sliders, but don't brush with butter. Cover and refrigerate. When ready to eat, brush with the seasoned butter, cover, and bake.