Grand Marnier Cake

In a small, non-aluminum saucepan, combine the liqueur, orange juice, lemon juice, sugar and salt. Bring to a boil, lower the heat and simmer until the sugar is dissolved and the syrup has thickened slightly, about six or seven minutes. Set aside to cool.

Cream together the butter and sugar until light and fluffy. Add the yolks of the eggs, sour cream and orange zest, and continue beating until the mixture is fluffy again and forms a ribbon.

Preheat the oven to 325 F. Lightly grease and then flour a nine-inch cake pan. Set aside.

In a large bowl, sift together the flour, baking powder and baking soda. Beat in the butter mixture, a little at a time, to form a smooth batter.

Beat the egg whites until they hold firm, glossy peaks. Fold the egg whites into the batter, making sure not to overwork it.

Pour the cake batter into the prepared pan and bake until puffed and golden brown, about one hour. A skewer inserted in the middle of the cake should come out clean.

Remove from the oven and let the cake cool on a rack for 30 minutes. When cool enough to handle, turn it carefully onto a plate. Pour the Grand Marnier syrup evenly over the cake, cover it, and refrigerate for at least a couple of hours or up to two days.