In a pan, heat the water and sugar until the sugar is dissolved.
Whisk together the eggs and egg yolks in a bowl.
Slowly add the hot liquid to the egg mixture while whisking continuously.
Pour this mixture back into the saucepan and cook over low heat for about 10 minutes or until it thickens.
Add the gelatin, vanilla bean, and salt to the custard and whisk until combined.
Stir in the banana puree and lemon juice and cook for another 2 minutes or until everything is well incorporated.
Remove from heat and let cool completely.