From Sunday Suppers At Lucques by Suzanne Goin
1 teaspoon saffron threads
3 tablespoons unsalted butter
3 tablespoons extra-virgin olive oil
5 cups sliced onions (about 1 1/4 pounds)
1 bay leaf
1 chile de árbol, crumbled
1 teaspoon thyme leaves
Kosher salt and freshly ground black pepper
Toast the saffron threads in a small pan over medium heat until they just dry and become brittle. Be careful not to burn the precious saffron. Pound the saffron in a mortar to a fine powder. Dab a tablespoon of the butter into the powder, using the butter to pick up the saffron.
Heat a large sauté pan or Dutch oven over medium heat for 2 minutes. Add the olive oil, remaining butter, and saffron. When the butter foams, add the onions, bay leaf, chile, thyme, 1 1/2 teaspoons salt, and some pepper. Cook 8 to 10 minutes, stirring often, as the onions wilt. Turn the heat down to low, and cook another 20 minutes, stirring every now and then, until the onions are soft and sweet. Taste for seasoning.