In a large saucepan, melt the butter over medium heat. Add the finely chopped onion and sauté until softened and fragrant.
Stir in the corn kernels and pour in the chicken broth. Bring the mixture to a boil, then reduce the heat to low. Cover the pan and let the soup simmer gently for about 15 minutes, allowing the flavors to meld together.
Remove 1 cup (250 ml) of the cooked corn kernels and set them aside for later use.
Carefully transfer the remaining soup to a blender and purée until smooth. For a silky texture, strain the blended soup through a fine-mesh sieve into a clean pot.
Stir in the cream, if using, and return the reserved corn kernels to the pot. Warm the soup gently over low heat, being careful not to boil if cream has been added.
Season with salt and pepper to taste. Serve hot and enjoy this creamy, comforting dish.