Use a small melon baller to scoop out about one-third of the top center portion of the onion, creating a well.

Place the onion on a sheet of aluminum foil and fill the well with vegan butter.

In a small bowl, mix the cajun seasoning, olive oil, and any optional seasonings. Pour this mixture over the butter, letting it dribble down the sides of the onion.

Season the outside of the onion with salt and any additional spices you desire.

Seal the entire onion tightly in aluminum foil and place it in a small baking dish or cast iron skillet to catch any drips.

Bake in a preheated oven at 400°F (200°C) for about 30-40 minutes, or until the onion is fork-tender and slightly caramelized. If it's still firm, reseal and bake for another 10 minutes.

Once ready, open the foil, drizzle with more melted butter or olive oil, add an extra pinch of salt, and broil for 5-10 minutes until golden brown.

When serving, peel away the outer layer of the onion and enjoy each layer with an extra sprinkle of salt, pouring over the delicious juices from the foil for maximum flavor.