For the curd, place the mango in a food processor and process until smooth. Add the sugar and lemon juice and continue to process until completely smooth.
Whisk the puree and the eggs together and pour into a pot. Cook over medium heat, stirring continuously for a few minutes. Next add the butter and cook until the mixture is thick enough to coat the back of a wooden spoon. Pour the curd through a fine sieve into a mixing bowl and cover with plastic wrap pressing the plastic onto the curd to prevent a skin from forming. Cool the curd before refrigerating for about 2 hours or overnight.
In the meantime, prepare the cake, beat the butter with the vanilla until light and creamy, add the sugar and beat until light and fluffy. Add the eggs one at a time, beating well after each addition. Add half of the flour and half of the milk and stir to combine. Add the remaining flour and milk and beat lightly until the mixture is smooth. Divide between 2 x 17cm cake tins and bake until cooked for about 30 – 40 minutes. Remove and set aside to cool before inverting the cakes onto a cooling rack to cool completely before applying the curd.
To assemble the cake, spread with a little curd between the layers and sandwich together. Pour the remaining curd over the cake and decorate as desired.