Combine the raisins and rum in a small bowl. Cover and set aside at room
temperature for at least 4 and up to 12 hours, stirring from time to time.
Combine the almond paste and 1/2 tablespoon water in another small
bowl. Mix thoroughly. Add 1/4 cup confectioners' sugar; cream with the
back of a spoon to a smooth paste. Using 1/4 teaspoon of the mixture
for each, shape almond-sugar into nuggets and drop onto a plate lined
with wax paper. Set the plate in the refrigerator, uncovered for at
least 2 hours.
Prepare the sponge starter by combining the yeast, 1 tablespoon of
the granulated sugar, and the milk in a small mixing bowl. Stir to dissolve
the yeast. Add 1/2 cup of the flour and stir until smoothly blended.
Cover with plastic wrap and set aside at room temperature until the
sponge has bubbled up and fallen back slightly, 30 to 45 minutes.
Cream 1/2 cup of the butter and the remaining 1/4 cup sugar in a large
mixing bowl. Add one whole egg and the yolk of the second, reserving
the egg white. Add the salt, lemon zest, vanilla, and spices, stirring
until smoothly blended. Add the sponge starter. Slowly add 1 3/4 cups
more flour. Mix the candied citron and almonds. Drain and add the raisins.
Turn the dough out on to a lightly floured work surface and knead
in 1/4 cup of the remaining flour. Continue to knead the soft dough
gently for 5 to 7 minutes, adding more flour as necessary, until the
dough feels smooth and moist but not sticky, and holds its shape when
pushed. Transfer to a greased large bowl, cover with plastic wrap, and
set aside at room temperature to rise until doubled, about 1 hour.
Return the dough to a work surface. Push or roll it out into a 15
x 9-inch oval, about 1/2 inch thick. Arrange the chilled almond nuggets
in 2 rows parallel to a long side of dough, covering about a third of
the surface. Beat the reserved egg white and the remaining 1 tablespoon
water in a small dish. Brush the exposed two-thirds of the surface of
the dough with the egg white and water wash and fold the dough over
the nuggets, leaving a scant 1/2 inch border.
Transfer the loaf to a nonstick baking sheet or one that has been
lined with parchment paper. Shape it into a crescent with the fold facing
out. Cover loosely with plastic wrap and set aside at room temperature
to rise for 30 minutes.
Preheat the oven to 350°.
Bake stollen for about 35 minutes, until golden brown.
Melt the remaining 2 tablespoons butter. Remove the pan form the oven
and brush the hot stollen with the melted butter. Cool on a wire rack,
then dust liberally with confectioners' sugar.
Cut the stollen into diagonal slices and serve warm. The stollen is
best freshly baked; I freeze half if I don't expect the whole loaf to
be consumed in a day or two.