I made these a few weeks ago in the oven. For yesterday's cookout, I thought they would be delicious cooked in a cast iron skillet over an open fire. Yes, these were even better.
Here's the recipe:
Peel and slice 3 or 4 Vidalia onions about 1/4 inch thick. Keep the rings together. Place in a buttered cast iron skillet and drizzle with olive oil. Top with kosher salt and freshly ground black pepper. Cover with foil and let cook over an open fire until onions begin to soften. Depending on how close to the fire you have the skillet and how the fire is, this should take about 30 minutes more or less.
Whisk together 3/4 cup of heavy cream and 1/2 cup white wine with 1 t. dried Italian seasoning. Slowly pour into the skillet and recover with foil. Let the liquid come to a boil and let onions simmer for about 10 more minutes.
Top with 1/2 - 3/4 cup freshly Parmesan/Reggiano cheese. Let cook until cheese melts and begins to brown.