• Heat the oil in a pan and cook the veggie burger according to the package instructions. Top with the vegan cheese and heat until melted. Remove from the pan and set aside.
• In the remaining oil, sauté the onions until soft, about 10 minutes.
• In a small bowl, combine the vegan mayo and ketchup.
• Assemble your burger! Spread each bun half with the mayo-ketchup spread and top with tomato slices, lettuce, and pickles. Place the veggie burger on one side of the bun, top with the other bun half, and enjoy!