• Preheat the oven to GM4/180 C and butter a9 x 13 oven trayor casserole dish leaving a 1 cm gap around the edges, do not butter the sides. Adjust oven rack to middle of oven.

Dry Ingredients

• Combine flour, baking powder and salt in a large bowl.

Eggs

• Seperate 5 eggs - Put the egg & yolks in 2 seperate bowls.
• Beat the egg whites on high until soft peaks form. This takes around a minute. With the machine still running, add 50g/1/4 cup caster sugar and beat on high until egg whites are stiff (1 - 2 minutes).
• Beat egg yolks with Lime Zest, 150g or ¾ cup Caster sugar on high speed, until yolks are a pale yellow (This takes 2 minutes). 
• Stir in 80g or ⅓ cup milk and Lime Juice into the yolk mixture.

Complete Cake batter

• Gently add the flour mixture to the egg yolk mixture. Then carefully fold in the egg whites. This takes some gentle persuasion but don't be tempted to rush it or be too heavy handed.
• Pour into tin/dish and bake for 25 – 30 minutes.

Tres Leches Syrup

• Make Milk mixture by combining evaporated milk, condensed milk, double cream, Lime and Cocoa powder in a bowl and whisk together.
• Once the cake has cooled, pierce all over with a fork and drizzle in the milk mixture. Leave to stand for 30 minutes.

Cream topping

• In a large bowl combine double cream and sugar and whip on high until thick. This takes around 3 - 5 minutes. Keep a very close eye on it though.
• Spread cream over the cake with a spatula then drizzle with melted chocolate and add Lime zest.

Additional Syrup

• Add all the ingredients for the syrup in a bowl and whisk together.

Serve

• Cut cake into pieces and add to bowls. Drizzle syrup around the cake and serve.