Create the corn cob broth by placing the reserved cobs and 2 cups (480 ml) of water in a pot with a tight-fitting lid.
Sprinkle with salt and pepper, bring to a boil, then reduce heat to a gentle simmer.
Cover and cook for about 30 minutes.
Remove the cobs and reserve the broth.
In a deep skillet or saucepan over medium-high heat, melt the butter or heat the oil.
Add the scallions and sugar, cooking for about 1 minute until soft.
Reduce heat to medium, stir in the flour, and cook, stirring constantly, for 5-10 minutes until the mixture is golden and the raw flour smell is gone.
Whisk in the milk and reserved corn broth, increase heat to medium-high, and stir constantly until the soup begins to thicken, about 2 minutes.
Stir in the fresh corn kernels.
Bring the soup to a boil, then reduce the heat to a gentle bubble.
Cook, stirring occasionally, for 10-15 minutes, until the corn is tender and the chowder has thickened to your liking.
Taste and adjust seasoning with salt and pepper.
Serve hot, garnished with cornbread croutons if desired.
Stir in 1/2 cup (480 ml) of grated sharp cheddar, Parmesan, or hard goat cheese along with the corn for a deliciously cheesy version.