In a large bowl, combine the ground beef, garlic powder, onion powder, salt, and pepper. Mix until just combined.

Divide the mixture into 8 equal portions and shape each portion into a small patty.

Preheat a grill or skillet over medium-high heat. Cook the patties for 3-4 minutes on each side, or until they reach your desired level of doneness.

During the last minute of cooking, place half a slice of cheddar cheese on each patty to melt.

While the patties are cooking, toast the slider buns on the grill or in a toaster until golden brown.

In a small bowl, mix together the mayonnaise, Dijon mustard, and ketchup to create a sauce.

Assemble the sliders by spreading the sauce on the bottom half of each bun, adding a patty with melted cheese, a slice of tomato, a handful of spinach, and pickles on top.

Place the top half of the bun on each slider and serve warm.