4 pounds yellow onions, peeled and cut into slices 1/8-inch thick
12 ounces unsalted butter
2-1/2 teaspoons kosher salt
1 teaspoon black pepper, freshly ground
2 teaspoons fresh minced herbs such as thyme, rosemary, sage or savory (optional)
Place onions, butter, salt and pepper in a heavy sauté pan. Cook slowly over low heat, stirring often. After 10 minutes, onions will begin to turn golden brown. If herbs are desired, add to onion mixture. Cook 15 to 20 minutes longer, until all onions are translucent, tender and golden brown.
Cool onions on a sheet pan in the refrigerator, then place in an airtight container and keep refrigerated until ready to use. Onions may be made ahead and kept refrigerated for up to 5 days. Reheat in a sauté pan over medium-low heat.
Makes 12 servings, 1/2 cup each.