Wash the lemons hot, grate them dry and finely grate the peel. Halve fruits and squeeze juice. Heat buttermilk and 2/3 lemon juice and grated lemon in a small pot. Mix 1 tbsp. cornflour with 1 tbsp. water and pour into the buttermilk mixture. Let simmer for about 5 minutes.
Cut the vanilla pod in half lengthwise. Scratch out the pulp with the back of a knife. In a bowl, whisk 4 egg yolks, 1/2 vanilla pulp and 3 tbsp. maple syrup with the whisks of the hand mixer until creamy. Add buttermilk mixture in portions and stir in. Cover the mixture with cling film and chill.
Cut the passion fruit in half and scrape out the flesh with a spoon. Heat the fruit flesh, orange juice and the remaining lemon juice and grated lemon juice. In a bowl, mix the remaining egg yolks, vanilla pulp, honey and maple syrup with the whisk of the hand mixer until creamy. Pour the passion fruit mixture through a sieve into the egg mixture and stir in.
Put the mixture into a pot and heat it up. Mix the rest of the starch with 1/2 tbsp. water and add to the passion fruit mixture. Heat it up for about 3 minutes while stirring constantly and let it simmer. Pour into a bowl, cover the mixture with cling film and chill.
Take both creams out of the fridge, stir until smooth and alternate in 4 glasses. Coarsely chop the pistachios and sprinkle on the cream.