Indonesian Spice Layer Cake (Spekkoek)

This is no ordinary cake. The baking process requires time and patience since the many layers (usually 18-20) are baked and grilled one at a time!
Makes 1 x 20 cm (8 in) round or square cake.
Ingredients
10 egg yolks
375 g/12 oz/11/2cups caster sugar
250 g/8 oz butter
2 teaspoons vanilla essence
8 egg whites
185 g/6 oz/11/2 cups plain (all-purpose) flour, sifted
1 teaspoon ground cinnamon
1 teaspoon freshly grated nutmeg
1 teaspoon ground cardamom
1/2 teaspoon ground cloves
extra melted butter (optional)
Directions
In electric mixer whisk egg yolks with 1/2 cup sugar until thick
and light. Cream butter with 3/4 cup sugar and the vanilla essence
until light and smooth. In a clean, dry bowl whisk egg whites until
stiff, add the remaining 1/4 cup sugar and whisk again until thick and
glossy.
Mix egg yolk and butter mixtures together well. Fold in the flour, then
the egg whites. Divide mixture into two almost equal portions and mix
the ground spices into the slightly larger portion.
Preheat oven to 160 degrees C (325 degrees F). Generously butter a 20
cm (8 in) springform cake pan with softened butter. Line the base with
baking paper and brush with melted butter. Dust with flour and tip out
excess.
Put a measured amount of spice batter into the tin, approximately 1/3
cup. Spread the batter thinly with a spatula and tap the tin very
firmly on the bench top to help the batter spread thinly and evenly.
Bake in the centre of the oven until firm, about 10 minutes. Meanwhile,
preheat grill and place the tin under the grill about 15 cm (6 in) from
the heat for 30-40 seconds until top is evenly browned. Watch carefully
to ensure it doesn't burn but achieves a coffee colour.
Spread the same amount of plain batter over the spicy layer, tapping
the tin to ensure a thin, even layer. Return to oven and cook for 10
minutes, then grill as before. Continue with alternate layers of spiced
and plain mixture until the batter has been used.
For those who enjoy a really buttery cake, the extra melted butter may
be used to brush lightly over each layer after grilling and before the
next layer of batter is spread over.When the last layer has been baked,
test by inserting a skewer into the centre. It should emerge slightly
buttery. If there is any uncooked batter clinging to it, bake the whole
cake for a few minutes longer. Cool completely, then remove the side of
the springform pan and cut the cake into thin, small slices as it is
very rich.
Recipe excerpted from Encyclopedia of Asian Food by Charmaine Solomon (Periplus Editions, 1998)