Use a fork to poke several holes in each potato.

Place the potatoes in a pot of cold water.

Add the teaspoons of the salt and the pinch of sugar.

Boil the potatoes until soft but not mushy. You want them a bit firm.

Remove the potatoes from the heat and drain. When the potatoes have cooled, peel and chop into little pieces. Set aside 2 tablespoons of the cooked chopped potatoes.

Chop the onions into small pieces.

Cut the corn kernels off of the cob. Set 2 tablespoons of kernels aside with the reserved potatoes.

Heat the butter and oil in a large pot over medium-high heat.

Add the onion and cook, stirring occasionally until they become transparent.

Stir in the potato pieces to combine. Stir in the corn. Season with salt and freshly ground pepper.

Add the heavy cream and vegetable broth. Bring to a boil, lower the heat to simmer, and cook for 15 minutes.

Season the mixture again to taste with salt and freshly ground pepper. Stir in the nutmeg.

Use a stick blender to puree the mixture until smooth. Or transfer the mixture to a food processor or blender, puree, and then transfer the mixture back into the pot.

Stir the chopped sage into the soup and cook the mixture for another 5 minutes.

Divide the soup among 4 bowls. Garnish with the reserved potato pieces and corn kernels. Sprinkle fresh sage or sage leaves over the top and serve.