Slice the onions. Toss frozen pearl onions with three to five minutes of boiling water. Run off.
Create the Roux recipe: Whisk flour into melted butter in a pan until a golden color and frothy mixture forms.
Cream Sauce: Whisk in heavy cream and vegetable broth gradually until smooth and thickened.
The sauce may be spiced up by adding nutmeg, salt, and pepper. Mix in half of the Parmesan.
Whisk Together: Whisk together the cream sauce and sautéed onions.
Place in a baking dish and top with the remaining Parmesan cheese before baking. Stick it in the oven at 375°F for around 15 to 20 minutes.
After allowing some time to cool, you may serve.
