To make the onion rings: heat about 2 inches of oil in a large, heavy-duty pot until a deep-fry thermometer reaches 360 degrees F.

In a large bowl, whisk together 1/2 cup of the flour, 1 teaspoon of the salt, the black pepper, garlic, paprika, baking powder, milk, and egg until smooth. Pour the remaining 1/2 cup flour into a shallow dish. Separate the onion slices into rings. Working with a handful of onion rings at a time, dredge in the flour, shaking off any excess and then dip into the batter.

Set a wire rack over a baking sheet. Preheat the oven to 250 degrees F.

Carefully place the battered onions in the hot oil, being careful not to over-crowd the pot, and fry until golden brown and crispy, about 3 minutes total. Flip over halfway through frying, drain and transfer to a paper towel-lined baking sheet. Season with a bit of salt to taste. Transfer to the wire rack and keep warm in the oven while you prepare everything else.

To make the sliders, preheat an outdoor grill or stovetop grill pan to medium heat. In a large bowl, mix together the ground beef, salt, pepper, garlic, and Worcestershire sauce. Shape into 12 even 2-inch wide patties and place on a plate or tray. Brush each side with oil, and place patties on the hot grill. Cook for about 4 minutes, turn over, and continue to cook for another 4 to 6 minutes, for medium rare, or 2 to 4 minutes longer if you want them well done. Place 2 pieces of cheese on each, along with 2 half pieces of bacon, and cook for a minute or two so the cheese melts. Close the grill or turn off the heat and transfer the sliders to a platter or tray.

To assemble the sliders, split the buns in half and spread each half with barbecue sauce. Place a bacon cheese slider on each bottom half, and top with a handful of of crispy onion rings, and a piece of lettuce. Replace the top half of the buns and skewer with a long toothpick. Serve immediately.