Char poblano peppers over open flame or under broiler until blackened on all sides. Place in bowl and cover with plastic wrap. Allow to steam for about 10 minutes. Run peppers under cool water rinsing away blackened skin.
Meanwhile, sauté onion in olive oil until tender. Add in corn and cook for another minute. Combine onion/corn mixture to 1 1/2 cups Cajun crab dip, along with 1/2 cup shredded cheese.
Slice pepper lengthwise and remove seeds. Generously fill each pepper with crab/corn mixture. Dip in beaten egg, then roll in cornmeal.
Preheat oven to 350 degrees.
Gently pan brown stuffed chiles then transfer to a baking dish. Top with remaining shredded cheese. Bake for 25 minutes, allow to rest for 5 minutes before serving.