Preheat oven to 350°F. Generously coat a 9-inch square glass or ceramic baking dish with baking spray with flour. Stir together flour, sugar, salt, and pepper in a small bowl, and set aside.

Pulse 1 cup of the corn kernels in a food processor until smooth, about 5 times, and set aside. Whisk eggs by hand in a large bowl until smooth and lightly beaten. Stir in flour mixture and milk until combined. Whisk in melted butter. Add corn puree, parsley, 1 tablespoon of the scallions, and remaining 2 cups corn kernels. Stir to combine well.

Transfer corn mixture to prepared baking dish. Bake in preheated oven until lightly browned, puffed up all over, and fairly firm, about 40 minutes. Sprinkle corn pudding with remaining 1/2 tablespoon scallions. Serve hot or warm.