• To start, sieve your flours together in a bowl, several times if you can be bothered. I've tried making this sponge with and without the sieving process and believe me it does make a difference.
• Add the egg whites to a mixer and using the whisk attachment beat into firm peaks.
• Add the caster sugar a table spoonful at a time and continue to beat until the whites become stiff and have a beautiful glossy sheen to them.

  TOP TIP: You know it's ready if you take a pinch a bit and rub your fingers together, if you can feel the sugar grains between your fingers you need to continue beating.
• Next add the egg yolks and whisk on slow, just enough to combine the two.
• Fold in the sifted flours quickly with a silicone spatula. Make sure you do this gently to prevent knocking too much air out of the mixture.
• Add to your well oiled and lined tin(s)
• Bake on 180°C | 160°C fan | 350°F | Gas 4 for 18-20 minutes – keep a close eye to make sure the sponge does not catch, you know this will be ready when you get a perfect spongy bounce to the touch….the cooked smell is unmistakable!
• Remove from oven and cool for 5 mins before gently removing from tin and placing on a damp tea towel (I run my tea towel under a hot tap and wring out while the sponge is baking.
• Gently peel off the baking paper. Now be brave and fold the end of tea towel over the short side of your sponge and gently begin to roll your sponge up away from you in a firm (but not too tight) roll. Your tea towel will roll up inside the sponge.
• You will end up with a rather odd looking fat rolled up tea towel on your cooling rack with your Genoise sponge tucked up nice and warm inside!
• Leave the sponge rolled for at least 10mins while you make your buttercream

To make the buttercream

• Simple add the butter or dairy free alternative to the clean mixing bowl along with the vanilla extract and boiled water and beat until light. Add the icing sugar in stages and beat for a prolonged period, the longer you beat the whiter and lighter the buttercream becomes.

To fill your Swiss Roll

• Gently unroll and dollop spoonful's of jam onto the bottom side (inner curl) of the sponge and smooth over the sponge with a pallet knife, this is actually the trickiest bit, covering the sponge with jam whilst the sponge tries to stay in a rolled up position.
• By now your sponge will have cooled enough to add the buttercream without it melting.
• To add your buttercream I strongly recommend using a piping bag, far less stressful and you won't end up smearing the jam around too. I use a round nozzle and simply pipe tight 'S' shape lines of buttercream over the curled sponge until all the sponge is covered in an even layer of butter cream from end-to-end and edge-to-edge.
• Now here comes the fun part. Your sponge will already know where it's going so gently re-roll the sponge being careful to not roll too tight causing your buttercream and jam to squeeze out of the sides.
• Place on a board or plate with the overlapped end downwards and dust with icing sugar.
• Breath a sigh of relief and make a well earned cup to tea to celebrate!