2 to 3 pounds fresh spinach
4 tablespoons butter
1 cup finely chopped yellow onion
6 cups chicken broth
2 cups (2 medium) Yukon Gold potatoes (peeled or unpeeled)
1 cup half-and-half
1 cup shredded Jarlsberg cheese
1/2 teaspoon salt
1/4 teaspoon ground white pepper
Trim the spinach, then stack leaves together and slice into slender strips. In a large skillet, melt the butter and saute the onion until soft and golden. Add spinach and continue to saute until leaves have wilted, about 1 minute; set aside.
In a large pot, heat the broth to boiling with the potatoes; reduce heat, cover and simmer until potatoes are very soft, about 20 minutes. Scrape spinach mixture into pot to combine. Using a hand-held blender or a food processor, blend mixture to cream potatoes and spinach, but don't overprocess; you want bits of spinach and potato to remain for texture.
Add the half-and-half and gently reheat soup, then drop the shredded cheese into pot, a little at a time, stirring after each addition until cheese melts. Add the salt and pepper to taste.
Makes 6 to 8 servings.