Preheat oven to 180C. Roll out two-thirds of pastry on a lightly floured surface to 3mm thick, line a 13cm x 36cm tart tin, trim edges and refrigerate until required. Roll out remaining pastry to 3mm thick, cut into 1cm strips and refrigerate on a tray until required.
Beat butter, sugar and orange rind until light and fluffy (1-2 minutes), then beat in eggs and liqueur, then almond meal. Spread in pastry case, filling to 1cm below rim (there may be a little left over). Bake until filling just sets (10-12 minutes), remove from oven, stand for 5 minutes. Spread with marmalade, then arrange pastry strips in a lattice pattern over the top. Brush lattice with eggwash, bake until pastry is golden (8-10 minutes), cool in tin to room temperature, dust with icing sugar and serve.