Brown the ground beef in a large skillet over medium-high heat for 5-7 minutes, breaking it into small crumbles as it cooks. Add diced onions during the last 2 minutes, stirring until softened. Drain excess fat, leaving about 2 tablespoons in the pan for flavor.
Add minced garlic to the meat mixture and sauté for 1 minute until fragrant. Stir in brown sugar, apple cider vinegar, smoked paprika, black pepper, cayenne pepper, Worcestershire sauce, and salt to taste. Let the spices bloom for 2-3 minutes as aromatic oils release.
Transfer the seasoned meat mixture to a slow cooker and stir in the cup of BBQ sauce until well combined. Cover and cook on low for 4 hours, stirring occasionally. The cozy game day sliders recipe develops deeper flavor as the sauce reduces and mingles with meat juices.
During the final 15 minutes of cooking, preheat your oven to 350°F. Butter the slider buns lightly and arrange them on a baking sheet. Toast the buns for 3-4 minutes until golden brown but still soft inside.
Remove the slow cooker lid and assess the sauce consistency—it should be thick and clingy, not soupy. If too wet, simmer uncovered for 10-15 minutes. If too thick, add a splash of beef broth or water.
Assemble the game day sliders by placing a spoonful of meat mixture on each toasted bun. Top with shredded cheddar cheese while meat is hot so it melts slightly. Add a small dollop of coleslaw for crunch and freshness.
Arrange assembled sliders on a serving platter and cover loosely with foil to keep warm. Serve immediately while cheese is melted and buns are still soft. These BBQ sliders taste best eaten within 20 minutes of assembly for optimal texture.