Creamed Onion Gratin

By BobLongo

Ingredients

• 3 pounds sweet onions (such as Vidalia, Walla Walla or Maui onions)
• 3 tablespoons cream sherry
• 6 tablespoons unsalted butter, divided
• 1/4 cup all-purpose flour
• 1 cup whole milk, scalded
• 1 cup freshly grated Parmesan cheese
• Kosher salt and pepper
• 1/2 cup panko crumbs

Preparation

Step 1

Preheat the oven to 375 degrees. Lightly grease a gratin dish or medium casserole.

Cut off the root and tip of the onions. Slice in half length-wise and peel. Lay the cut-side of the onion down and slice length-wise into thick wedges.

In a Dutch oven or heavy pot, melt two tablespoons of butter over medium heat. Add the onions and cook, stirring occasionally, until soft and caramelized, about 40 minutes. Add the sherry and simmer until it evaporates. Remove the onions from the pan and pour through a fine mesh sieve. Let them drain while making the béchamel sauce. (Draining the onions prevents a runny gratin because the onions will continue to release more liquid in the oven.)