In a bowl, mix the cream butter and sugar. Add 3 eggs, one at a time, beating well after each. Beat in lemon peel, orange peel and vanilla. Combine the flour, baking powder and salt; gradually add to creamed mixture. Divide dough into four portions; shape each into an 20 x 5cm rectangle on ungreased baking sheets.

In a small bowl, lightly beat remaining egg; brush evenly over dough. Sprinkle with almonds.
Bake at 180°C for 25-30 minutes or until lightly browned. Cool for 5 minutes. Transfer to a cutting board; cut diagonally with a serrated knife into 2cm slices.

Place cut side down on ungreased baking sheets.
Bake for 12-14 minutes or until golden brown, turning once. Cool on wire racks.

Dip the biscotti in the glass of Muscat for a couple of seconds and enjoy