Step 1

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.

Step 2

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.

Step 3

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.

Step 4

Preheat the oven to 350°F. Lightly grease a large baking sheet. Separate the tops from the bottoms of the slider buns. Fit the slider bottom buns tightly on the baking sheet.

Step 5

Evenly distribute the beef and onion mixture over the bottom buns. Top with the gruyere cheese. Cover with the top buns.

Step 6

In a microwave safe bowl, melt the butter with the remaining beef base. Stir in the remaining Worcestershire sauce and continue to mix until well-combined. Using a pastry brush, brush the beefy butter mixture over the top buns. Sprinkle with the sesame seeds, thyme, onion powder, and garlic powder.

Step 7

Bake the sliders until the cheese is fully melted and the tops of the rolls are lightly browned, about 20 minutes.