1. Roll out the pastry to a strip measuring 66 x 10 - 11.5 cm (26 x 4 - 4 1/2 inches). Cut the pastry lengthways into 1-cm (1/2-inch) ribbons with a sharp knife.
2. Moisten one edge of each strip and wind each round a cream horn tin starting at the tip, overlapping 0.3 cm Q inch), and finishing neatly on the underside. The pastry should not overlap the metal rim. Brush with beaten egg to glaze.
3. Arrange the cream horns on a dampened baking sheet, join-side down.
4. Bake in the oven at 220°C (425°F) mark 7 for 10 minutes until golden brown.
5. Cool for a few minutes then carefully twist each tin, holding the pastry lightly in the other hand to ease it out of the pastry horn.
6. When cold, fill the tip of each horn with a little jam. Whisk the two creams together until stiff and fill the horns down to the jam. Dredge with sifted icing sugar.