Frozen Lemon Cream Meringue Cake

-FOR 3 CUPS LEMON CREAM-
1 Stick unsalted butter; (1/
-cup)
3/4 c Sugar
1/2 ts Cornstarch
1/2 c Fresh lemon juice; (about 2
-lemons)
1 tb Freshly grated lemon zest
1 Whole large egg plus 6 large
-egg yolks
1 c Plain yogurt

FOR THE ICING
1 1/2 ts Unflavored gelatin
3 tb Orange-flavored liqueur
1 1/2 c Heavy cream
Lemon slices and unsprayed
-lemon leaves
; for garnish

Make the meringue layers:

Line a buttered baking sheet with parchment paper or foil and on it trace 2
squares, using the top and bottom of a 9-inch-square pan as a guide (one
square will be slightly larger than the other). In a large bowl with an
electric mixer beat the whites with a pinch of salt until they hold soft
peaks, add the sugar, 1 tablespoon at a time, beating, and beat the whites
until they hold stiff, glossy peaks. Transfer the meringue to a pastry bag
fitted with a 1/2-inch tip, pipe it to fill in the squares, and smooth the
tops. Bake the meringues in the middle of a preheated 275�F. oven for 1
hour, or until they are firm when touched lightly and very pale golden.
Remove the meringues with the parchment from the baking sheets, let them
cool, and peel off the parchment carefully. With a serrated knife trim the
meringue layers so that the smaller one will just fit inside the bottom of
the pan and the larger will just fit inside the top of the pan. Reserve the
trimmings.

Oil the pan with vegetable oil and line it with plastic wrap, leaving about
a 5-inch overhang all around. Put the smaller meringue layer, smooth side
down, in the lined pan. Stir the reserved meringue trimmings, crumbled,
into the lemon cream, pour the filling into the pan, smoothing it, and top
it with the remaining meringue layer, smooth side up, pressing gently. Fold
the plastic-wrap overhang over the top to enclose the cake. Freeze the
cake, wrapped well, overnight, or until it is frozen solid.

Make the icing:

In a small saucepan sprinkle the gelatin over the orange-flavored liqueur,
let it soften for 1 minute, and heat the mixture over low heat, stirring,
until the gelatin is dissolved. In a bowl beat the cream until it just
holds stiff peaks, add the gelatin mixture in a stream, beating, and beat
the icing until it holds stiff peaks.

Unwrap the cake and unmold it onto a serving plate, discarding the plastic
wrap. Spread a thin layer of the icing on the top and sides of the cake.
Transfer the remaining icing to a pastry bag fitted with a decorative tip
(such as basketwork one) and pipe it over the cake. Chill the cake for no
more that 1 1/2 hours, decorate it with the lemon slices and leaves, and
cut it into squares with a serrated knife.

Make the lemon cream:

In a heavy saucepan melt the butter with the sugar, the cornstarch, the
lemon juice, and the zest over moderately low heat, stirring until the
sugar is dissolved. In a bowl whisk together lightly the whole egg and the
yolks and add the butter mixture in a stream whisking. Transfer the mixture
to the pan and cook it over moderately low heat, whisking constantly, for 3
to 5 minutes, or until the curd is thick enough to hold the mark of the
whisk and the first bubble appears on the surface. Transfer the curd
immediately to a bowl, cover its surface with plastic wrap, and let the
curd cool. Chill the curd, covered with the plastic wrap, for 1 hour, or
until it is cold. Whisk the yogurt into the curd, chill the lemon cream,
and serve it with berries or as a filling for frozen lemon cream meringue
cake. Makes about 3 cups.