Step 1

Grease a 15cm x 13cm tin with oil. Mix together the icing sugar and cornflour and sift over enough to cover the base.

Step 2

Put the gelatine sheets into a bowl of cold water and leave for 5 minutes until softened.

Step 3

Put the granulated sugar and liquid glucose into a small pan with 100ml water and set over a low heat until completely dissolved.

Step 4

Bring the syrup to the boil until a teaspoon of the mixture becomes a hard ball when dropped into a bowl of cold water and you can bring it together with your fingers (if you’re using a thermometer, it should be 124°C). Plunge the base of the pan into a sink of cold water to stop it cooking any more.

Step 5

Squeeze the gelatine to remove excess water and stir into the sugar syrup. In another bowl, whisk the egg white until stiff. With the whisk still running, trickle in the sugar syrup/gelatine mixture. Keep on whisking until it is thick and glossy, then whisk in the elderflower cordial and a dab of green food colouring – use the tip of a cocktail stick and keep adding until happy with the colour. Turn into the tin, smooth out and leave to set overnight.

Step 6

Sift more of the icing sugar/cornflour mixture over a large piece of baking parchment and tip the set marshmallow on top. Dust the top again and leave for 1 hour. Cut into squares and toss the elderflower marshmallows in the icing sugar mixture.