1. Cut ½ inch off the neck of the onion and peel off the outer layers of papery skin. Place the peeled onion in a bloom cutter, root side down, and cut.
2. Take one package of batter mix and prepare it according to package instructions. The batter should have the consistency of milk or light cream. Dip the onion in the mixed batter, making sure the batter gets between all the petals. Remove and turn upside down to drain excess batter.
3. Coat the battered onion in the second, dry package of batter mix. Separate the petals, making sure all surfaces are coated. Remove and turn upside down, gently tapping to remove all excess dry batter. Turn onion right side up and allow coated onion to set for 5 minutes before frying, to allow the onion and batter to merge.
4. Heat a deep fryer to 375 degrees. Fill with enough vegetable oil to cover the onion. Place bloom in oil, right-side up, with a large slotted spoon. Cook for 4 to 5 minutes or until golden brown. Remove and allow to drain for several minutes before serving.