ingredients1 tablespoon butter 4 cups corn kernels seeded and finely chopped 1/4 cup red onion finely chopped 1 jalapeno seeds and ribs removed, then finely chopped 1/2 cup fresh cilantro leaves chopped, plus more for garnish 3 tablespoons lime juice 1/4 cup mexican crema or sour cream 2 tablespoons mayonn