This recipe makes a rich, smooth cream sauce (a béchamel) that is then combined with the tender onions.
Ingredients
1 pound pearl onions (fresh or frozen, see notes below)
4 tablespoons (1/2 stick) unsalted butter
1/4 cup all-purpose flour
2 cups whole milk or half-and-half (or Matt uses heavy cream)
1/2 teaspoon salt (or to taste)
1/4 teaspoon freshly ground black pepper
Pinch of ground nutmeg (optional, but classic)
3 tablespoons parmesan cheese
Instructions
1. Prepare the Onions
If using fresh pearl onions: Bring a pot of water to a boil. Blanch the onions for 1-2 minutes to loosen the skins. Drain, run under cold water, trim the root and stem ends, and peel.
Cook the Onions: Place the peeled fresh onions (or frozen onions) in a medium saucepan. Cover them with water or chicken broth, add a pinch of salt, and bring to a simmer. Cook for about 5-10 minutes, or until the onions are tender when pierced with a knife.
Drain: Drain the onions well and set them aside. (Some traditional recipes reserve a cup of the cooking liquid and use it in place of some milk for extra onion flavor, but the recipe below uses only milk/cream for a richer taste).
2. Make the Béchamel Sauce (The Cream)
Melt the Butter: In a medium saucepan, melt the 4 tablespoons of butter over medium heat.
Make the Roux: Whisk in the 1/4 cup of flour to form a smooth paste (this is the roux). Cook, stirring constantly, for about 1-2 minutes. This cooks out the raw flour taste—do not let it brown.
Add the Milk: Slowly pour in the 2 cups of milk (or half-and-half) while constantly whisking to prevent lumps.
Thicken: Continue to cook and stir over medium heat. Bring the mixture to a gentle simmer and cook until the sauce is thick enough to coat the back of a spoon, about 5-7 minutes.
3. Season and Combine
Season: Remove the sauce from the heat and whisk in the salt, pepper, and nutmeg (if using). Taste and adjust seasoning as needed.
Combine: Gently fold the cooked pearl onions into the cream sauce until they are completely coated.
Serve: Serve immediately, or transfer to a small baking dish and bake at 350°F for about 15-20 minutes, or until bubbly and slightly golden on top.
Tips and Variations
Aromatics: For an extra layer of flavor, add a pinch of thyme or a bay leaf to the milk while it's heating, removing it before mixing with the roux.
Extra Richness: Use half-and-half or heavy cream instead of whole milk for a more decadent sauce.
A Tangy Kick: A splash (about 1-2 tablespoons) of dry sherry or white wine, added to the sauce after it thickens, can give it a lovely dimension.
Cheesy Onions: Stir in a few tablespoons of finely grated Parmesan or Gruyère cheese at the end for a richer, savory finish.
