1. Cook onions in large pot with boiling water until tender. Remove and allow to cool. Peel the onions and set them aside. 2. In a saucepan, melt the butter over medium low heat. Add the flour and stir. 3. Pour in the chicken broth and heavy cream and simmer. Stir until thickened. 4. Remove the pan from heat and stir in the parsley and parmesan cheese. 5. Add the onions and stir to coat. 6. Transfer to baking dish. Cover and store in fridge overnight. 7. Before cooking, bring to room temp. 8. Bake at 350 the onions covered for 15 minutes, then remove the cover and cook an additional 10 minutes, until the sauce is bubbly.