Old-fashioned Vanilla Icebox Cake

Heat the oven to 350 degrees. Butter and flour two 8- by 3-inch cake pans.
In the bowl of an electric mixer using the paddle attachment on medium
speed, cream together the butter, sugar, and vanilla seeds until light and
fluffy, about 3 minutes. To obtain the seeds, slit the vanilla bean
lengthwise, and scrape the interior. Sift together the flour and baking
powder. On low speed, add the dry ingredients, alternating with the milk,
starting and ending with flour; scrape down sides twice. Transfer batter to
a large bowl. In the clean bowl of an electric mixer fitted with the whisk
attachment, whisk the egg whites on low speed with the pinch of salt until
foamy. Increase speed to high, and continue to whisk until stiff (but not
dry) peaks form, 3 to 5 minutes. Whisk in one-third of the beaten whites
into the batter to lighten the mixture. Using a large rubber spatula, fold
remaining whites into the lightened batter. Divide the batter equally among
the prepared pans. Bake until golden brown and a cake tester inserted into
the center comes clean, 40 to 45 minutes. Remove the pans to a rack to cool
for 5 minutes. Invert the cakes onto the wire rack to cool completely. To
make the Cr?me Fra?che Frosting: In the bowl of an electric mixer fitted
with the whisk attachment, whip the cr?me fra?che, confectioners’ sugar,
and candied lemon zest on medium-low speed until thick and creamy, about 3
minutes. Cover with plastic wrap, and refrigerate at least 1 hour. (Makes 6
cups) To make the Candied Lemon Zest: Place the zest in a small saucepan.
Cover with cold water and bring to a boil. Strain, reserving the zest.
Repeat the process 3 more times. Return zest to small saucepan. Pour 1 cup
water and 1/3 cup sugar over blanched zest. Bring to a boil over medium
heat. Reduce heat to simmer. Simmer until the zest appears translucent, 10
to 15 minutes. Remove from the syrup with a slotted spoon to a wire rack to
dry, about 30 minutes. (Makes about 3 tablespoons) To assemble, place one
layer, top-side down, on a cake stand. Spread a 1/2-inch layer of frosting.
Repeat with remaining layers. Lightly coat the assembled cake in a layer of
frosting to protect against crumbs in the frosting. Finish with remaining
frosting. Garnish with candied lemon zest. Keep refrigerated. Makes 1
eight-inch layer cake.