This simple, savory onion gratin contains Italian red torpedo onions which are meltingly sweet when baked. A crisp breadcrumb crust gives just the right savory hint for a recipe that's excellent in early fall.
Melt the butter in a cast iron skillet over a medium flame until it begins to foam, toss the sliced onions into the hot fat and fry them, stirring frequently, until they release their fragrance and become tender and translucent.
Preheat the oven to 425 degrees Fahrenheit.
While the oven preheats, reduce the heat to medium-low, pour two cups cream into the skillet over the onions and simmer them together until cream thickens and is reduced by half, about fifteen minutes.
In a separate bowl, stir two cups whole grain sourdough bread crumbs with two tablespoons minced fresh thyme and one-quarter cup minced Italian flat-leaf parsley. Season the mixture of breadcrumbs and herbs with unrefined sea salt as it suits you.
Remove the onions and cream from the heat. Top them with seasoned breadcrumbs and one-half cup grated pecorino romano cheese.
Place the onion gratin in an oven preheated to 425 degrees Fahrenheit and bake for twenty to twenty-five minutes or until the season breadcrumbs and cheese form a nice golden crust and the cream begins to bubble.
All the onion gratin to rest for about five minutes before serving.