Preheat the oven to 170°C/325°F/Gas Mark 3. Grease the base and sides of a 23cm/9in round springform tin, and line
the base with parchment paper. Place the baking tin onto a lipped baking sheet, the batter is very runny so this catches any that might escape at the start of baking.
In a large bowl beat the eggs using an electric hand-held whisk/stand-alone mixer for approximately 2 minutes, until they are pale and fluffy.
Add the condensed milk, melted butter and vanilla extract and beat just until they are mixed through.
Sift in the ground almonds, cocoa powder, baking powder and salt, and gently fold through until evenly incorporated.
Pour into the prepared baking tin (it will be very runny so don’t panic) and bake in the preheated oven for 40 minutes. The cake is done when a skewer inserted into the centre comes out clean. Remove from the oven and allow to cool in the tin for 15 minutes before transferring to a wire rack to cool completely. Dust with icing sugar.