AT A GLANCE
You'll need a large (5-litre) mixing bowl on your electric mixer to make the buttercream; otherwise make it in two batches. I prefer the precision of weight measurements for all ingredients, which is usual practice for pastry chefs.
|01||Preheat oven to 175C. Butter three 20cm-diameter cake tins, dust with flour and line bases with baking paper. Combine flour, sugars, baking powder, and ½ tsp salt in an electric mixer fitted with a paddle. Add butter and mix until sand-textured.|
|02||With mixer on low speed, add 260gm milk, increase speed to medium and beat for 2 minutes to aerate the batter. Meanwhile, combine eggwhite, yolk, vanilla, and remaining milk in a bowl, then add to batter in 3 batches, beating well each time.|
|03||Divide mixture between the cake tins and bake, rotating cakes once after 20 minutes, until cooked (25-35 minutes; the centres should spring back when lightly pressed). Cool in tins for 10 minutes, then turn out onto a wire rack to cool.|
|04||For Swiss meringue buttercream, combine sugar, eggwhite, glucose and ¾ tsp salt in a bowl place over a saucepan of simmering water and half-stir, half-whisk until mixture reaches 50C-53C (8-12 minutes).|
|05||Transfer to an electric mixer and whisk on medium-high speed until cooled (10-15 minutes), then start adding butter a little at a time until it is all incorporated. Add vanilla and colour buttercream with food colouring, or whiten with titanium dioxide. Buttercream will keep stored in the refrigerator for a week; bring to room temperature before using and fluff up again in an electric mixer.|
|06||Transfer half the buttercream to a piping bag fitted with a flat or petal tip (Wilton 125) nozzle.|
|07||Turn cakes up the right way and cut in half horizontally.|
|08||To assemble, place a cake round on a lazy Susan or piece of baking paper to turn the cake as you go, spread with a heaped tablespoon of jam, leaving a 5mm border, then spread with a good half-cup of buttercream right to the edges. Repeat layering with cake, jam and buttercream, finishing with a cake round.|
|09||Using a spatula, spread a little frosting all over the cake to seal the crumb.|
|10||Starting at the base, pipe ruffled ribbons up the side and all around the cake until covered, then pipe circles to cover the top, refilling the bag as necessary. Any buttercream left over can be refrigerated or frozen for another use.|
Note Cake flour is available from select supermarkets; to make it, remove 2 tbsp from each cup of plain flour, and replace with 2 tbsp cornflour. Titanium dioxide is a whitening agent available from cake-decorating suppliers.