Petrale sole in brown butter-caper sauce

It’s a brown butter kind of fall.

That is to say, the nutty flavor and butterscotch aroma of butter cooked until it becomes hazelnut brown are turning up on more than a few dinner plates around town -- in sweet corn ravioli and in mashed potatoes at Melisse in Santa Monica, with sweetbreads and a four-spice blend at Spago in Beverly Hills, and in ice cream and financiers at Hatfield’s in Los Angeles.

There’s nothing new about brown butter -- known in French as beurre noisette. It’s just that lately L.A. chefs have been drizzling it, whisking it, incorporating it with uncommon glee.

Quinn and Karen Hatfield, chef-owners of Hatfield’s, love brown butter so much they named the company that owns their restaurant Brown Butter LLC. “It’s a flavor you can’t duplicate, so original, so nutty, so deep,” Karen Hatfield says.

Making brown butter is simple: Melt unsalted butter in a small saute pan over medium heat, cooking it until the water cooks off, then turn down the heat and continue cooking, whisking constantly, until the solids turn golden brown. The whisking ensures even browning. If you have a light-colored pan, that’s the one to use, as it makes it easy to see the browning.

That’s it.

Brown butter is fabulous spooned over roasted kabocha squash, drizzled over Brussels sprouts or steamed cauliflower, or stirred into mashed potatoes.

Add fresh sage and it’s a great sauce for ravioli filled with pumpkin or butternut squash.

Fattening? Yes. But a little goes a long way.

A squeeze of lemon juice turns it into a wonderful sauce for fish. To make any delicate fish fillet or whole small fish a la meuniere (petrale sole, rex sole and trout are all ideal), coat the fish lightly with flour, saute it in a little butter and remove it to a platter. Pour out the butter in the pan, add fresh butter and cook, whisking until it’s brown butter. Whisk in a little lemon juice, pour it over the fish and you’ve got a la meuniere.

Or substitute vinegar for the lemon, add capers and call it an easy, snazzy dinner. (That’s a classic preparation for skate.)

Josiah Citrin, Melisse’s chef-owner, says he loves to use brown butter to finish sauces. He uses it in a Champagne reduction sauce for fish, in a bearnaise sauce and in a balsamic vinegar and brown butter vinaigrette fortified with lobster reduction, which he uses to sauce lobster.

On the sweet side, brown butter stirred into frosting is great for drizzling over cookies or into batters for quick breads. Use it in place of plain butter in the fruit fillings of apple or quince pies for added depth. “Any opportunity I get to melt butter,” says Sherry Yard, pastry chef at Spago, “I continue on to the noisette stage. It adds a wonderful complexity to the dessert.” When making a genoise for a cake she drizzles brown butter in at the end of making the batter.

Scrape vanilla bean into the brown butter and spoon it over poached pears or baked apples. “A whisper of salt makes the flavors dance on the tongue more,” Yard says.

Citrin suggests making a large batch of brown butter, then chilling it in a glass baking dish before cutting it into cubes and freezing it. It’s a convenient way to have brown butter on hand for finishing sauces or adding flavor in an instant.