Red Onion Gratin
The View From the Great Island
Red Onion Gratin ~ the onion bakes up soft and sweet in a cheesy sauce finished off with a crunchy herb crumb topping in this unusual gratin!
- 2 red onions
- olive oil for brushing
- 2 tbsp unsalted butter (divided)
- 1 tbsp all purpose flour
- ⅔ cups heavy cream
- 3 tbsp dry sherry
- salt and fresh cracked black pepper
- dash of nutmeg (I grate mine fresh)
- handful of fresh thyme
- 1 cup shredded Gruyere cheese
- ½ cup fresh breadcrumbs
- Set oven to 400F
- Peel and thickly slice the onions.
- Heat a grill pan until quite hot, and brush the onion slices lightly with olive oil. Grill the slices for a minute or two on each side so that they get slightly softened and have nice grill marks. Set them aside.
- In a saucepan, heat 1 Tbsp of the butter over medium heat, and stir in the flour. Cook for a minute, stirring constantly. Pour in the cream and sherry and whisk until smooth. Stir constantly while the mixture comes up to a simmer and is thickened. Add salt and pepper to taste and the dash of nutmeg.
- Pour the sauce into a cast iron skillet or gratin dish. Arrange the onion slices over the sauce.
- Sprinkle the cheese evenly over all.
- Stir the breadcrumbs together with the last tablespoon of melted butter, and a little salt, pepper, and a few thyme leaves. Sprinkle the breadcrumbs over the cheese,
- Bake for about 20 minutes until browned and bubbling. You can run the gratin under the broiler at the last minute if you want extra browning,