Ingredients:
8 Tbsp (1 stick) butter, divided
2 large sweet onions, sliced
2 lb ground beef
2 Tbsp beef base (such as Better than Boullion), divided
1 Tbsp Worcestershire sauce, divided
Kosher salt and black pepper, to taste
24 slider buns
12–16 oz gruyere cheese, chopped
2 Tbsp sesame seeds
1 Tbsp fresh thyme
1 tsp onion powder
1 tsp garlic powder
Directions:
1. Melt 2 Tbsp butter in skillet over medium heat.
Add in onions and reduce heat to medium low.
Cook, stirring occasionally, until lightly caramelized, about 25-30 mins.
If onions start to look dry or burnt, add a tablespoon of water to pan.
2. In large bowl, mix ground beef with half of beef base and half of Worcestershire sauce.
Season with salt and pepper.
3. Add beef to skillet full of onions.
Increase heat to medium-high and brown beef, breaking it up and mixing with onions as you go.
Once browned, drain off excess grease.
4. Preheat oven to 350°F. Lightly grease large baking sheet.
Separate tops from bottoms of slider buns. Fit slider bottom buns tightly on baking sheet.
Evenly distribute beef and onion mixture over bottom buns.
Top with gruyere cheese. Cover with top buns.
5. In microwave safe bowl, melt remaining butter with remaining beef base.
Stir in remaining Worcestershire sauce and continue to mix until well-combined.
Using pastry brush, brush beefy butter mixture over top buns.
Sprinkle with sesame seeds, thyme, onion powder, and garlic powder.
6. Bake sliders until cheese is fully melted and tops of rolls are lightly browned, about 20 mins.