The pastry shells can be made in advance and stored at room temperature.
- 1 package frozen puff pastry shells (we used Pepperidge Farm, 8 per package)
- ½ stick unsalted butter
- 2 pounds Vidalia onions (about 3 or 4), trimmed and cut into thick slices ½ – ¾ inch thick
- 1 tablespoon minced garlic
- 1 bay leaf
- ¼ teaspoon freshly grated nutmeg
- 1 small bunch fresh thyme, tied with twine or wrapped in cheese cloth
- 1 tablespoon fresh sage, cut into slivers
- 1 teaspoon Kosher salt
- ¼ teaspoon freshly ground black pepper
- ½ cup heavy cream
- ½ cup vegetable stock
- 1 cup grated Romano cheese
- Corn starch, as needed
- Preheat oven to 425 degrees. Bake pastry shells according to package directions and set aside.
- In a medium heavy bottomed pan or Dutch oven, melt butter over medium heat and add onions. Sauté over medium for ten minutes just until they become a little flexible but not cooked through. Add garlic, bay leaf, nutmeg, thyme, sage, salt, pepper, cream and stock and bring to a boil then reduce to a simmer.
- Simmer for 15 minutes stirring occasionally and then add the Romano cheese.
- Stir again and continue to simmer for five minutes or until the sauce thickens and the onions are tender. If the onions become tender before the sauce has thickened, mix a little corn starch and water and drizzle a small amount in and stir over heat until it reaches the desired thickness. Alternatively add more cream if it is too thick. The onions should be tender but not mushy and the sauce should be thick and creamy.
- Remove the bay leaf and thyme and discard.
- Place a pastry shell on a serving dish and pop the top off and remove the center dough. Then fill the center with the creamed onions, spilling over the edges. Place the pastry top back on over the onions, then serve immediately.