Prep the Veggies for Perfection: Heat 1 tablespoon of olive oil in a large skillet or frying pan over medium-high heat. Add the sliced onions and cook, stirring occasionally, until softened and lightly caramelized, about 5-7 minutes. The trick to avoiding greasiness and achieving perfect texture is to ensure the pan is hot and not overcrowded. Add the red and yellow bell peppers and zucchini. Continue to cook, stirring frequently, until the vegetables are tender-crisp and slightly browned, about another 7-10 minutes. Ensure they are spread in a single layer as much as possible to achieve proper caramelization and prevent them from steaming and becoming watery. Season generously with salt and pepper to taste. Remove the perfectly cooked vegetables from the skillet and set aside.

Cook the Patties: Form the ground beef into 6 small, thin patties, slightly wider than your slider buns. Season both sides with salt and pepper.

Sear the Patties: In the same skillet (add a little more olive oil if needed), increase heat to medium-high. Place the patties in the hot skillet and cook for 2-3 minutes per side for medium doneness, or until desired doneness.

Melt the Cheese: During the last minute of cooking the patties, place a slice of cheese on top of each patty. To ensure an ultra-melty finish, you can cover the skillet with a lid for about 30-60 seconds, allowing the steam to perfectly melt the cheese over the hot patties.

Toast the Buns (Optional but Recommended): While the cheese melts, lightly toast the slider buns in a separate dry skillet or a toaster if desired.

Assemble the Sliders: Place a cheesy patty on the bottom half of each slider bun. Top generously with the perfectly cooked, vibrant, and flavor-packed vegetables. Place the top bun on each slider and serve immediately for an unforgettable bite!