2 to 3 pounds fresh spinach
1/2 cup chopped yellow onion
1 garlic clove, pressed or peeled and finely minced
2 tablespoons butter or olive oil (or a combination of both)
1 tablespoon flour
1 cup heavy cream
1/2 teaspoon salt (more or less to taste)
1/8 teaspoon white pepper
Pinch of nutmeg
Wash the spinach thoroughly in a large amount of water to remove grit; trim away tough stems and withered or yellowed leaves.
Bring 6 quarts of salted water to a rolling boil. Add spinach, a handful at a time so water will remain at a boil. Once all spinach has been added, boil for 1 to 2 minutes (if leaves seem old and tough, give them a full 2 minutes; otherwise, 1 minute is fine). Remove pot from burner, carefully place it in the sink and run cold tap water into pot. Continue doing this until spinach is floating in very cold water, which will stop cooking and set color.
Strain cold spinach into a colander, then firmly squeeze leaves to remove all water (if you can't bring yourself to allow so many nutrients to escape, do this last process over a bowl and save liquid for soup or stew). At this point, spinach can be covered and refrigerated for later preparation.
When ready to proceed, chop enough blanched spinach to measure about 2 cups; set aside.
Saute the onion and garlic in the butter over medium heat until onion is soft and translucent, about 5 minutes. Add chopped spinach and continue cooking for a few minutes, then sprinkle on the flour and stir to blend into spinach. Add the cream, salt and pepper and continue cooking and stirring over medium to medium-high heat until cream sauce has reduced and thickened slightly.
Remove spinach from heat, carefully scrape it into a food processor (without burning yourself) and process using "pulse" switch or "on-off" action to avoid overprocessing mixture. The idea is to bring mixture to a stage at which some dark-green flecks of spinach remain; it shouldn't look like cream of spinach soup. Serve immediately or gently reheat.
Makes about 2 2/3 cups, enough for 6 servings.