Overnight Coffeecake

1 cup milk, divided
2 (1/4 ounce each) envelopes dry yeast
1/2 cup warm water (100 to 110 degrees)
4 cups flour
1  1/4 cups sugar, divided
1 teaspoon salt
2 sticks butter, cut up
3 egg yolks, lightly beaten, plus
1 egg yolk, divided
3 egg whites
2 teaspoons plus 1 tablespoon cinnamon, divided
1  1/2 cups chopped toasted hazelnuts, divided
1 cup powdered sugar, sifted
1 teaspoon dark rum  (optional)
1/4 teaspoon vanilla

In a small saucepan, heat three-fourths cup milk to scalding. Remove from the heat and let cool to warm.

Sprinkle the yeast over the warm water and stir until the yeast is completely dissolved.

In the large bowl of an electric mixer, combine the flour, one-fourth cup sugar and the salt. Work in the butter by hand or with a pastry cutter until the mixture resembles cornmeal.

Combine three lightly beaten egg yolks, the warm milk and the yeast mixture. Add to the flour mixture and beat at medium speed until completely blended and a soft dough forms, about one minute.

Divide the dough into two parts and shape each into a ball. Put each into a lightly buttered bowl. Cover and refrigerate overnight.

Remove the dough from the refrigerator; let it stand 30 minutes. Heat the oven to 350 degrees.

While the dough is standing, beat the egg whites until light and foamy. Gradually beat in the remaining one cup sugar until stiff peaks form. Beat in one teaspoon of the cinnamon. Fold in one cup of the chopped toasted hazelnuts.

Take one of the dough balls, shape it into an oval and, on a lightly floured board, roll it out to form a 10- by 18-inch rectangle.

Spread half of the meringue mixture onto the rolled-out dough, leaving a 1-inch border. Roll up the dough lengthwise, jellyroll style. Pinch the ends of the roll to seal.

Gently lift the roll onto a large greased baking sheet, seam side down, and form it into a horseshoe shape. Cut slashes halfway through the dough at 2-inch intervals.

Repeat the process with the remaining half of the dough.

Invert a large bowl over each of the coffeecakes. Set aside to rise about 45 minutes or until doubled.

Lightly beat one egg yolk and two tablespoons milk. Brush each of the coffeecakes with this egg wash, brushing the entire surface of the dough, but do not brush the meringue filling that shows.

Bake 30 to 35 minutes, until golden brown, turning the baking sheet halfway through. Cool on the pan for about five minutes before glazing.

For the glaze, stir together the powdered sugar, the remaining two tablespoons milk, the rum, if using, and the vanilla. Drizzle it over the coffeecakes. Sprinkle the cakes with the remaining one-half cup of chopped nuts.

Servings: 20 (eight to 10 per coffeecake)

Variations:
Orange: Follow the master recipe, stirring two teaspoons grated orange peel into the filling. Replace one cup of the hazelnuts with toasted, slivered almonds. For the glaze, substitute two tablespoons orange juice for the milk and stir in one teaspoon grated orange peel. After glazing, warm the coffeecakes and sprinkle one to two tablespoons chopped candied orange peel over the top of each. Omit the nuts on top.

Pecan: Follow the master recipe, replacing hazelnuts with toasted pecans in the filling. For the glaze, heat one-fourth cup butter over low heat until nut-brown, about five to six minutes. Remove from heat and let cool. Combine three-fourths cup powdered sugar, one-fourth cup firmly packed light brown sugar, the browned butter, two tablespoons milk, two tablespoons maple syrup and one-fourth teaspoon vanilla. Drizzle the glaze over warm coffeecakes, warming it in the microwave if necessary to maintain drizzling consistency. Sprinkle with one-fourth cup toasted pecan pieces.

Chocolate: Follow the master recipe, stirring one-fourth cup chopped semisweet or bittersweet chocolate into the filling along with chopped hazelnuts. Omit cinnamon. Sprinkle chopped hazelnuts and one-fourth cup chopped chocolate over the warm, glazed coffeecakes.