Ingredients

• butter
• for greasing
• 3 free-range eggs
• 115g/4oz caster sugar
• plus 4 tbsp for dredging
• 1 unwaxed lemon
• zest only
• 115g/4oz plain flour
• 200g/7oz icing sugar
• sifted
• 125g/4½oz softened butter
• 2 tsp freshly squeezed lemon juice
• 125g/4½oz lemon curd

Directions

• Preheat the oven to 200C/400F/Gas 6. Grease and line a 33cm x 23cm/13in x 9in Swiss roll tin with buttered baking parchment.
• Put the eggs
• 115g/4oz sugar and the lemon zest in a heatproof bowl.Place over a pan of gently simmering water. Whisk with an electric whisk until the mixture is pale
• creamy and thick enough to leave a trail when the whisk is lifted. Carefully remove the bowl from the heat and continue whisking for a further five minutes.
• Sift in half the flour and
• using a large metal spoon
• lightly fold it into the egg mixture. Sift in the remaining flour and fold into the mixture - it’s important to use gentle movements to retain as much air as possible in the batter.
• Pour the mixture slowly into the prepared tin and gently spread with a spatula so the base of the tin is evenly covered.
• Bake for 10–12 minutes until well-risen
• pale golden-brown and firm to the touch.
• Place a damp tea towel on the work surface and cover with a sheet of baking parchment. Dredge with the four tablespoons of sugar – this will help stop the outside of the sponge sticking. Working quickly
• turn the cake out onto the sugared paper and carefully remove the lining paper.
• Using a sharp knife
• cut off the crusty edges from the two long sides. Roll the Swiss roll from one of the short ends
• starting with a tight turn to make a good round shape and keeping the sugared paper inside the roll. Set on a wire rack and leave to cool.
• To make the icing
• put the icing sugar and butter in a bowl and beat until smooth and creamy. Add the lemon juice and beat again.
• When the cake is cold
• gently unroll but do not flatten it or it could crack. Spread the cake with then lemon butter icing
• leaving a 1cm/½in border. Spoon the lemon curd evenly over the icing. Slowly roll the cake up again
• enclosing the filling
• and place on a plate. Sprinkle with extra sugar if you like.