Melt unsalted butter in a large skillet over medium-high; add minced sweet onion, and cook until softened, about 5 minutes. Stir in fresh corn kernels and water. Cover and cook 10 minutes.

Transfer half of corn mixture to a blender. Remove center of blender lid; secure lid, and place a clean towel over opening. Process until smooth. Add puree to skillet; stir in heavy cream, kosher salt, pepper, and nutmeg. Cook over medium until thickened and heated through. Top with breadcrumb and parmesan mixture. Bake at 375 for 20 minutes. Garnish with chopped fresh parsley.