Soak gelatin in cold water for 5 minutes.
Split the vanilla pod and make sure to scrape out the seeds. Squeeze the juice from the lemons.
Then, cook the vanilla seeds, lemon juice, and sugar in a pot until the sugar has melted.
When ready, “squeeze” the water out of the gelatin and stir it into the sugar syrup.
Whip the cream until fluffy and set aside.
Make sure your sugar syrup is just “finger-warm” before adding the buttermilk in a thin stream.
Then fold in the whipped cream.
Soak gelatin in cold water for 5 minutes.
Cook the frozen mango pieces in a pot with 3 tablespoons of cold water, 1 teaspoon of vanilla sugar, and a little lemon juice for about 5 minutes.
Remove the pot from heat. Use an immersion blender until the mango is completely smooth. Add the gelatin and stir it around in the pot with the mango until it is melted.
Pour the mango jelly into a small bowl and place it in the freezer for 30-45 minutes until it has set.
Pour the cold buttermilk mousse over the mango jelly and place it in the fridge until set (4-5 hours) - It can easily be made the day before.
Serve the cold buttermilk mousse with small pieces of fresh mango and crushed ladyfingers on the side.