Christmas Cherry Spirals

In large bowl, beat butter with sugar until light and fluffy. Beat in egg and vanilla. Combine flour, baking powder and sa< with wooden spoon, stir into butter mixture in 3 additions. Divide in half. Tint 1 of the halves with red food colouring; stir in cherries to make sticky dough. Flatten each half slightly; wrap in plastic wrap and refrigerate for at least 1 hour or until chilled. (Make ahead: Refrigerate for up to 1 day.)

Between waxed paper, roll out plain dough to 14- x 8-inch (35 x 20 cm) rectangle. Repeat with red dough. Brush plain dough with egg white. Holding by paper, invert red dough onto plain dough. Roll lightly with rolling pin; remove top paper. Trim edges.

Using bottom paper as guide, tightly roll up from long edge; roll back and forth to seal seam. Wrap in plastic wrap; refrigerate for at least 1 hour or until chilled.

Place roll, seam side down, on work surface; with sharp knife, cut into 1/4-inch (5 mm) thick slices. Arrange, 1 inch (2.5 cm) apart, on parchment paper-lined rimless baking sheets. Bake in top and bottom thirds of 375°F (190°C) oven, rotating and switching pans halfway through, for about 10 minutes or until firm. Let cool on pan on rack for 1 minute. Transfer to rack; let cool completely. (Make ahead: Store in airtight container for up to 1 week or freeze for up to 2 weeks.)