Method

• 1.
  Preheat oven to 180°C/160°C fan-forced. Grease a 20cm round cake pan and line with baking paper.
• 2.
  Put the butter in a small saucepan and melt it over a low heat. Leave it until it becomes foamy and starts to smell amazing, then set it aside to cool. If you have a few burnt bits, strain them out and discard. If you prefer a less toasty flavour, you can just melt the butter and take it off the heat before it starts to brown.
• 3.
  Whisk the eggs, sugar and vanilla in a stand mixer fitted with the whisk attachment on medium-high speed for around 10 minutes. The mixture should triple involume and become pale and creamy.
• 4.
  In a separate bowl, mix the flour and 1/4 tsp fine salt with your fingers. Sift a third of the flour mixture over the egg mixture, then use a spatula to gently fold it in, ensuring you scrape the side and bottom of the bowl to get an even mix. Repeat with half the remaining flour mixture, and then the last of it. Once the flour is almost mixed through, pour the butter over the top of the mixture and fold it in until just combined.
• 5.
  Pour the mixture into the prepared pan and gently even out the top with the spatula. Put it on the top shelf of the oven. Bake for 20 minutes before checking (cake is done when a skewer inserted in centre comes out clean). If required, rotate cake and bake for another 1-2 minutes.
• 6.
  Leave the cake to cool in the pan for 5 minutes before turning out onto a wire rack to cool completely.
• 7.
  To make the filling and topping, combine 300g raspberries with 50g sugar and the lemon zest and juice in a small saucepan. Place over medium heat and bring to the boil, then reduce heat to low and simmer for around 15 minutes, until slightly thickened. Set it aside to cool completely, then add the remaining raspberries and mix them through.
• 8.
  In a separate bowl, whisk the cream and creme fraiche or sour cream with the remaining sugar and vanilla until soft peaks form. Add two-thirds of the raspberry compote to the whipped cream and gently fold it through to create a ripple effect.
• 9.
  Carefully cut the completely cooled sponge in half horizontally. Place the bottom half on a plate and top with half of the raspberry ripple cream. Use an offset spatula to spread it evenly over the cake, leaving a 1cm border around the edge. Dollop a few spoonfuls of raspberry compote over the top of the cream, leaving half for the top of the cake.
• 10.
  Place the other half of the cake on top and gently press it down until the filling just reaches the edge. Spread the remaining raspberry ripple cream evenly over the top and use an offset spatula to create a wavy pattern. Dollop remaining raspberry compote on top, and serve.