Preheat your oven to 350°F and line a baking sheet with parchment paper. Set it aside while you prep the fillings.

In a large skillet over medium-high heat, cook the ground beef with the onions and garlic until the beef is browned and no longer pink, breaking it apart with a spatula as it cooks. Drain off any excess grease.

Transfer the cooked beef to a large bowl and stir in the secret sauce, salt, pepper, smoked paprika, and garlic powder. Mix everything together and set aside.

In the same skillet, cook the bacon until crispy. Once it’s cooled slightly, crumble it into bite-sized pieces and set aside.

Use a bread knife to slice the slider buns in half horizontally (keeping the tops connected) and place the bottom half on your prepared baking sheet.

Layer 6 slices of cheddar cheese evenly over the buns, then spread the beef mixture on top. Add the remaining 6 slices of cheese, followed by the crumbled bacon. Finish with the top half of the buns.

In a small bowl, combine the melted butter, Dijon mustard, brown sugar, and Worcestershire sauce. Microwave for about 10 seconds if needed to melt the butter fully, then stir to mix.

Brush the butter mixture evenly over the tops of the buns, then sprinkle with sesame seeds.

Tent the sliders with foil and bake for 15–20 minutes. Remove the foil and bake for another 5 minutes if you want the buns extra toasty.

Serve warm — as is or loaded up with extras like pickles, red onion, tomato slices, or shredded lettuce.