In a large skillet heat 1 tablespoon of the olive oil over medium heat. Add corn and onion. Cook and stir about 5 minutes or until onion is just tender. Remove from heat; cool slightly. Place half of the corn mixture in a food processor. Cover and process until nearly smooth. Transfer to a large bowl. Stir in buttermilk and egg.
In another bowl stir together the polenta mix, flour, baking powder, baking soda, and salt. Add the polenta mixture to the buttermilk mixture and stir just until combined. Stir in the remaining corn mixture.
In a very large skillet heat remaining 1 tablespoon olive oil over medium heat. For each corn cake, pour about 1/4 cup batter into hot skillet; spread batter if necessary. Cook over medium heat about 2 minutes on each side or until golden brown. Add more oil to skillet as needed when frying remaining cakes. Spoon relish over corn cakes and, if desired, top with basil. Makes 6 (2-cake) servings
In a bowl combine 1 large seeded and chopped red sweet pepper, 1-1/2 cups fresh corn kernels, 1/2 cup chopped onion, and 1/4 cup chopped basil. Stir in 1 tablespoon olive oil. Add salt and pepper to taste.