Corn Potage (コーンポタージュ) is a French-influenced Japanese corn soup that's rich, creamy and ultra-smooth. My version is made with just a handful of ingredients with loads of umami accented by the natural sweetness of the corn.
Add the butter and onions to a pot over medium heat and sauté until the onions are just starting to brown (about 10 minutes).
If you’re using fresh corn, use a sharp knife to remove the corn from the cob. Use the back side of your knife to scrape any remaining bits of corn off the cob.
When the onions are ready, add the corn, potato, milk, and salt to the pot and simmer until the potatoes are tender (about 10-15 minutes)
While the soup is cooking, make the croutons by melting the butter in a pan over medium heat and then adding the cubed bread. Toss to coat with the butter and then sprinkle with salt and pepper. Continue tossing until the bread is crisp and golden brown.
When the potatoes are tender, pour the mixture into a heat-safe blender. Secure the lid tightly and hold a thick dishcloth firmly over the blender(this is very important as the sudden release of steam will make the lid fly off and send hot soup flying all over the kitchen).
Start the blender on low and gradually turn up the speed until the soup is pureed.
Clean out the pot and pass the soup through a fine-mesh strainer. Press on the solids with the back of a spoon to get as much of the soup out of them as possible. Reheat the soup if needed and serve the Corn Potage garnished with the croutons and chopped parsley.