Fill a large bowl or pot with ice and water and set aside.

Bring a large pot of water to a boil; add the onions and cook them for 1 minute. Transfer the blanched onions to the ice water to halt the cooking process. Drain and peel the onions.

Put the peeled onions in the same large pot with 1 teaspoon of salt. Cover the onions with water and bring to a boil. Reduce the heat to low, cover the pan, and simmer the onions for about 20 minutes, or until tender.

Set a colander over a bowl; drain the onions, reserving the cooking liquid; set both aside.

In the same pan, melt the butter; add the flour. Cook for about 2 minutes, stirring constantly. Gradually add the half-and-half and continue to cook until the sauce mixture thickens and begins to bubble, stirring constantly.

Add the pepper and nutmeg. Taste and add salt, as needed. If the sauce is too thick, add some of the reserved liquid.

Add the drained cooked onions to the sauce; heat through and serve.