In a large skillet, heat over medium-high heat and add the ground beef and sausage. Stir occasionally for about 7-10 minutes until browned. Drain excess grease.

Transfer the meat to a saucepan. Reduce heat to low and add cubed Velveeta, black pepper, and onion powder. Stir continuously until the cheese melts, about 3-5 minutes.

Preheat broiler and toast the slider buns for 1-2 minutes until golden brown. Spoon the meat and cheese filling onto the bottom half of each bun, cover with the top half.

Serve the assembled sliders warm and allow guests to add toppings like pickles, jalapeños, or bacon.