Prep the onion cutting off about 1 inch of the top and bottom and then removing the outer layers of the onion. Turn the onion over so the base is on a flat surface and then starting at the top, cut lengthwise through the onion all around, leaving about ¼ inch on the bottom and not cutting through for every cut. Each cut should be 1-2 inches from each other so you end up creating 6-7 sections.
Coat the onions well in oil with a pastry brush.
In a food processor, blend all of the ingredients for the vegan parmesan cheese until the mixture is finely ground.
Then sprinkle on the vegan parm + blackened seasoning and mix it in again with the oil by brushing it with the pastry brush.
Spray the grill with oil and warm it to medium heat (200-300 degrees).
Add the onions with the base down onto the grill and cook for 25 minutes or until onions become more translucent.
While the onions are cooking, mix together the Lime Aioli in a small bowl.
Remove carefully from the grill by using a spatula.
Serve with the lime aioli as a dipping sauce and ENJOY!