Occasionally, when I want to serve an expensive main course, I search for less expensive sides to even out the plate. Last week I chose onions, but in one of those odd synchronistic moments, three of us shopped for food. The result was a glut of onions. In fact, pounds of onions.
Onions keep really well but we had so many onions that it was doubtful that they would all survive even with the quantity of cooking we do around here.
Each of us bought some fresh salmon also so we had plenty of main course ingredients! That’s an easy fix though: salmon grilled, salmon cakes and salmon in frittata for breakfast. So, I went to work on creating side dishes from onions. This is when I became thankful for the Gratin!
A gratin is any dish wherein the ingredients are topped with cheese and/or breadcrumbs and then heated until the topping is all browned and crispy making a crunchy crust. They are usually assembled in ovenproof, shallow containers that allow large surface areas to insure that the topping will be crisp. A gratin can also be referred to as “au gratin” or “gratinée.”
2 very large onions (mine were almost a pound apiece)
Olive oil for drizzling over the onions
1 Tablespoon fresh thyme
Sea salt and fresh ground pepper, to taste
¼ cup white wine (choose something dry like a chardonnay)
1 cup heavy cream
2 teaspoons Dijon mustard (use gluten free if you are gluten intolerant)
¼-scant ½ cup Parmesan, Romano or Gruyère cheese (I had a smattering of each so I combined them into just over a ¼ cup of cheese. It’s a loose measurement in this case.)
Optional: seasoned breadcrumbs to cover the casserole.
(If you are gluten intolerant, you can omit the breadcrumbs without compromising the flavor or quality of this recipe.)
Preheat the oven to 450˚.
Peel and slice the onions into thick rounds.
Lay the rounds in an oiled baking sheet. Keep them in a single layer.
Drizzle the onions with olive oil or brush them to coat.
Season the onions with salt, pepper and fresh thyme.
Bake in the oven for 15 minutes. At this point, the onions should become translucent and even show a touch of golden brown.
While the onions bake, combine the wine, heavy cream and Dijon mustard in a saucepan over medium high heat, stirring to combine. Bring the mixture to a bubbling and turn off the heat.
By now, the onions should be finished baking. Remove them from the baking sheet and put them into your gratin pan or a shallow casserole.
Pour the cream mixture over the onions. Return the onions to the oven and bake for another 25 minutes. Remove from the oven.
Top the casserole with the breadcrumbs (if using) and the grated cheese. Return to the oven until the top is golden brown, approximately 10-12 minutes more.
This recipe is quite flexible so increase the quantities if necessary. Using these ingredients, the recipe yielded 6 moderate sized servings. You can supplement the onions with leeks and shallots too.
Serve while hot!