Crack the eggs, separating the egg yolks and egg whites into two different bowls
Add the egg whites into one bowl and whip until soft peaks form – soft peaks have formed when the cream forms peaks briefly when you lift the whisk before fall back into the cream
Add the caster sugar then whip further until medium peaks form before setting aside – medium peaks have formed when the cream can form peaks that hold their shape well when the whisk is lifted but have a slightly curled top
To the egg yolks add the milk and vanilla extract then mix until well combined
Sift the plain flour and baking powder into the batter then whisk until there is no trace of flour – be careful not to overmix as this will give a dense cake
Line a 20cm/8-inch square cake tin with parchment paper
Bake in the centre of preheated oven at 175°C/320°F/gas mark 3 for 30-35 minutes
In a jug mix the evaporated milk, sweetened condensed milk and double cream together
Once the cake is ready usea fork to poke holes into the warm cake then pour the milk bath on to the cake – you can use a spoon to push the liquid into the cake
Leave the cake to rest for at least an hour – the cake can be left to soak overnight
When ready to serve prepare the whipped cream by adding the double cream, icing sugar and vanilla extract to a cold bowl and whisk until stiff peaks are about to form
Transfer the whipped cream into a piping bag with a star nozzle then pipe onto the cake and top with crushed pistachios
Your tres leches cake is ready!