In a heavy bottomed pot, add enough oil to reach 4 inches up the sides. Preheat to 365 degrees F.
In a medium-sized bowl, combine the flour, paprika, onion powder, salt, and baking powder. In a small bowl, whisk together the buttermilk and egg. Add the wet mixture to the dry mixture, whisking the batter until just combined. In a medium bowl or wide baking dish, add onion rings and dust with flour. Toss gently to uniformly coat rings, and shake off excess flour. Working in batches, dip floured onion rings into the batter, making sure they are thoroughly coated, then carefully add to the preheated oil. Cook until deep golden, flipping halfway through if necessary, about 2 minutes. Remove the onion rings to a paper towel-lined plate and season immediately with salt. Transfer to a serving platter and serve hot. No ketchup needed!