Grease a 22cm springform cake tin with soft butter and line the bottom with baking parchment. Shake a little flour around the buttered edges.
Melt the chocolate, Rodda’s clotted cream, and butter together over a pan of simmering water, or in a microwave. Once melted, whisk together until smooth and add the espresso.
Whisk the egg yolks with the brown sugar and caster sugar, for 5-10 mins until thick and pale.
In a separate bowl, using a clean whisk, beat the egg whites and cream of tartar until soft rounded peaks form.
Pour the chocolate mixture onto the beaten yolks and sugar, and gently mix until smooth. Add the almonds and flour and mix again. Spoon the egg whites into the chocolate mixture and gently fold together.
Pour the batter into the prepared tin and bake for 40-45 minutes until the cake is set but with a slight jiggle in the centre.
Allow to cool and serve with a dusting of cocoa powder, a generous spoonful of Rodda’s Cornish clotted cream and fresh strawberries.