IF SERVING HOT: Preheat oven to 350 degrees. If serving cold or making ahead, skip this step.
In a large bowl use a hand mixer on low speed to mix together the cream cheese, mayonnaise, corn kernels, celery, bell pepper, green onion, cajun seasoning, garlic powder, and salt and pepper until well combined.
Add in the lump crab meat and cheese and mix on low just until combined.
If baking, pour the dip into a 9x9 inch baking dish, top with extra shredded cheese if desired, to taste. Bake for 15-20 minutes until hot and bubbly.
If serving cold, add the dip to an airtight container and chill for at least one hour before serving.
Serve this dip with your favorite crackers, chips, and veggies for dipping.