My mom used to make these for us. Now my neighbor brings it over when we are recovering from a flu.

Step 1: Prep the Onions: Bring a large pot of water to a boil. Add the peeled pearl onions and blanch for 2 minutes. Drain immediately and transfer the onions to an ice bath to cool. Trim the ends and ensure all outer skin layers are carefully peeled away.
Step 2: Make the Creamy Sauce (Roux and Béchamel): In a saucepan over medium heat, melt the butter. Whisk in the flour to create a roux. Cook the roux for 2-3 minutes until it is golden brown. Gradually whisk in the whole milk and heavy cream, ensuring no lumps form. Bring the sauce to a gentle simmer and stir frequently until it thickens.
Step 3: Season and Simmer: Season the sauce generously with nutmeg, salt, and white pepper. Add the blanched and peeled pearl onions to the sauce. Simmer gently for 15-20 minutes, or until the onions are completely tender.
Step 4: Serve and Enjoy! Once the onions are tender and the sauce has reached your desired consistency, remove from heat. Garnish generously with chopped fresh parsley before serving.