French Onion Beef Sliders For A Crowd

INGREDIENTS
8 tablespoons (1 stick) butter, divided
2 large sweet onions, sliced
2 pounds ground beef
2 tablespoons beef base (such as Better than Boullion), divided
1 tablespoon Worcestershire sauce, divided
Kosher salt and black pepper, to taste
24 slider buns
12–16 ounces gruyere cheese, chopped
2 tablespoons sesame seeds
1 tablespoon fresh thyme
1 teaspoon onion powder
1 teaspoon garlic powder

INSTRUCTIONS
Melt 2 tablespoons of the butter in a skillet over medium heat. Add in the onions and reduce the heat to medium low. Cook, stirring occasionally, until lightly caramelized, about 25-30 minutes. If the onions start to look dry or burnt, add a tablespoon of water to the pan.
In a large bowl, mix the ground beef with half of the beef base and half of the Worcestershire sauce. Season with salt and pepper.
Add the beef to the skillet full of onions. Increase heat to medium-high and brown the beef, breaking it up and mixing with the onions as you go. Once browned, drain off excess grease.

Full Recipe