Ingredients

makes about 12

　　11 tablespoons (1 3/8 sticks) unsalted butter, softened, plus more for the bowl, plus 5 tablespoons melted

　　1 envelope (1/4 ounce) active dry yeast

　　1 tablespoon sugar

　　2 tablespoon warm water (105° to 110°F)

　　3/4 cup buttermilk

　　1 large egg, lightly beaten

　　2 3/4 cups plus 2 tablespoons all-purpose flour, plus more for the surface and pin

　　2 teaspoons salt

　　2 pounds sweet onions, such as Rio (1 1/2 pounds cut into 1/4-inch slices, 1/2 pound finely chopped)

　　1/8 teaspoon freshly grated nutmeg

　　

Step 1

Butter a 9-inch cake pan using 1 tablespoon softened butter. Butter a large bowl; set aside. Stir together the yeast, sugar, and warm water in a small bowl; let the mixture stand until foamy, about 5 minutes. Stir until dissolved. Stir in the buttermilk and egg.

　　

Step 2

Mix 2 3/4 cups flour and 1 1/2 teaspoons salt in the bowl of an electric mixer fitted with the dough hook. Make a well in the center. Pour in the buttermilk mixture; mix to combine. Add 6 tablespoons softened butter; mix on medium-high speed until a soft dough forms, about 10 minutes.

　　

Step 3

Scrape the dough onto a lightly floured work surface; sprinkle with the remaining 2 tablespoons flour. Knead the dough until smooth, about 5 minutes. Transfer to the buttered bowl. Cover the dough with a clean kitchen towel; let rise in a warm place until doubled in bulk, about 1 hour.

　　

Step 4

Melt the remaining 4 tablespoons softened butter in a large saucepan over medium-high heat. Add the onions; raise heat to high, and cook, stirring often, until soft, about 5 minutes. Reduce heat to medium; cook, stirring, until golden brown, about 30 minutes. Stir in the nutmeg. Season with 1/2 teaspoon salt. Let cool.

　　

Step 5

Punch down the dough, and turn out onto a lightly floured work surface. With a lightly floured rolling pin, roll the dough into a 17 × 10-inch rectangle, and brush with 3 tablespoons melted butter. Spread the onions evenly over the dough. Starting on 1 long side, roll the dough into a log. Press the seam to seal.

　　

Step 6

Cut into about 12 slices, about 1 1/4 inches thick each. Arrange the slices, cut sides up, in the buttered pan, and brush with remaining 2 tablespoons melted butter. Cover loosely with plastic wrap. Let rise in a warm place until doubled in bulk, about 50 minutes.

　　

Step 7

Preheat the oven to 375°F. Bake the rolls until golden brown, about 35 minutes. Immediately invert the rolls onto a wire rack. Serve warm.

　　Reprinted with permission from The Martha Stewart Living Cookbook: The New Classics by Martha Stewart Living Magazine, copyright © 2007. Published by Clarkson Potter, a division of The Crown Publishing Group.Buy the full book from Amazon.