Fry about 3 minutes, then turn the onion over and cook until golden, about 3 more minutes; drain on paper towels. Season with salt and serve with the dip. How to Slice a Bloomin' Onion. 1. Cut off 1/2 inch from the pointy stem end of the onion, then peel. 2. Place the onion cut-side down.Starting 1/2 inch from the root, make a downward cut all the way through to the board.ry about 3 minutes, then turn the onion over and cook until golden, about 3 more minutes; drain on paper towels. Season with salt and serve with the dip. How to Slice a Bloomin' Onion. 1. Cut off 1/2 inch from the pointy stem end of the onion, then peel. 2. Place the onion cut-side down.