- Combine balsamic vinegar, 2 tablespoons olive oil, jalapenos, garlic, soy sauce, and black pepper and pour over beef. Cover with plastic and let marinade overnight in the fridge.
- Preheat grill to 375°F and place beef onto hot grill. Grill for 15-20 minutes on each side or until it reaches desired doneness. Remove from heat and tent with foil for 10 minutes. Cut into 1 inch slices.
- While the beef is on the grill, heat 2 tablespoons of olive oil in a skillet on medium heat. Add onions and salt and cook until the onions are well caramelized, 20-25 minutes.
- When you’re ready to serve, toast the slider buns by placing face down on the grill. This should take only a few minutes.
- To assemble sliders, place 1-2 slices of beef on the bottom slider bun and top with a spoonful of onions. Spread ½ tablespoon ofsriracha mayo on the top half of the bun and place on top of the slider.