Combine desired amount of salt, pepper and garlic powder into a small bowl.
Cover outside of london broil with spices
Place a meat thermometer into the london broil
Cook for ~1 hour and 15 minutes or until temperature reads ~125 for medium rare
Let cool.
Slice sweet onion into thin rings.
Heat a large skillet over medium heat.
Add olive oil, honey and onions.
Stir occasionally cooking for about 15 minutes or until onions become caramelized.
Once beef has cooled. Cut meat as thin as possible.
Place beef on sliders and top with spring mix, gouda, and caramelized onions.
Notes
RECIPE TIPS AND SUBSTITUTIONS:Store leftover roast beef in an airtight container (keep it whole and slice when ready to eat). Toast slider buns until golden brown to add a little crunch to your Roast beef and cheese sandwiches.If you like to add a little spice to your slider, try topping it with horseradish sauce.If you don't have any gouda cheese you can substitute with Swiss cheese, provolone cheese, or cheddar cheese. I wouldn't really recommend parmesan cheese though. It's too dry for this.