In another bowl, cream the butter and sugar with an electric mixer. Add the egg yolk and beat until the mixture is smooth. Using a wooden spoon, mix in the dry ingredients. Spread the dough into a 14 x 4-inch (35 x 10 cm) rectangular tart pan with a removable bottom. Using your fingertips, firmly press the dough into the bottom and sides of the pan. Refrigerate for 30 minutes.
Figs with Port