These impressive teatime treats are surprisingly easy to make and would look amazing as part of a celebratory afternoon tea. The pastry horns can be made ahead of time and stored in an airtight container for 2-3 days. Once filled they should be eaten straight away, or stored in the fridge for up to a day.
Preheat the oven to gas 6, 200°C, fan 180°C. Unroll the pastry and cut into 1cm (1/2in) strips down the longest side. Lightly oil your hand and coat the horn moulds with oil (use metal moulds or make your own, see tip).
Starting at the pointed end, wrap a pastry strip around the mould in a spiral, with each line overlapping slightly. Repeat to cover all the moulds. Brush the pastry all over with the beaten egg and sprinkle with demerara sugar.
Place the horns on their sides on a non-stick baking tray and put into the oven for 10–12 minutes, or until the horns are golden-brown and crisp. Transfer to a wire rack to cool completely. Once cool, carefully remove the moulds (using a clean tea towel to help you).
Whizz half the raspberries in a food processor. Lightly whip the cream in a bowl, until soft peaks form. Add the caster sugar and vanilla seeds and mix to combine. Fold the blended raspberries through the cream.
Spoon the cream in a piping bag fitted with a large star nozzle, pipe the mixture into the cream horns and top with the remaining fresh raspberries. Serve immediately.
Tip: To make your own horn moulds, use paper plates covered with double thickness non-stick foil. Fold them into cones, 12cm (5in) long with a diameter of 1 1/2cm (3/4in) at the wide end.