Lime marshmallows

Heat castor sugar, glucose, lime rind and half the water in a saucepan. Stir to dissolve sugar. Bring to the boil, brushing down sides of saucepan with a wet pastry brush.

Once sugar syrup has boiled, remove lime rind with a slotted spoon and discard. Continue boiling syrup.

Meanwhile, sprinkle gelatin over remaining water in a heat-proof bowl. Stand in a simmering pot of water and stir until gelatin has dissolved.

Once sugar syrup reaches 120C, add lime juice and gelatin and return to the boil.

Whisk egg whites in an electric mixer until stiff peaks form. With the motor running, add syrup by pouring it down the side of the bowl. Add food colouring. Continue to whisk until mixture has cooled and is thick.

Combine cornflour and icing sugar. Lightly grease a 20-centimetre-by-30-centimetre tin and dust with some of the cornflour mixture to evenly coat. Pour in marshmallow and smooth over the top.

Leave to set for one to two hours.

Turn out onto a board dusted with cornflour mix and cut into squares. Clean knife with a wet cloth between cuts.

Toss squares in remaining cornflour mix and stand on a rack to dry.

If desired, mix lime zest with sugar and top each marshmallow with a pinch.

Store in an airtight container.