Cut the potatoes into small pieces and boil them. Slice the onion thinly.

Toast the bread in a pan with butter until golden and crispy.

Heat butter in a pan and sauté the sliced onion until soft and fragrant.

Blend the sautéed onion, boiled potatoes, and milk in a blender until smooth.

Transfer the blended mixture to a pot and simmer while stirring to thicken.

Season the soup with salt and sugar, adjusting to taste.