Preparing the butter caramel and miso:

Melt 30 g butter with the white miso in a pan. Add the apple juice and a little water 
to completely dissolve the miso.
Preparing the leek and apple:
Cut the leek into slices about 1 cm thick. Slice the Golden Delicious apple and use a peeler to cut out small cylinders. Add the leek and apple to the pan with the butter caramel and miso, browning them for a few minutes.
Tarte tatin composition:

Place the leek and apple golden side down in a tartlet mould. Drizzle with the rest of the caramel and cover with the shortcrust pastry. Bake in the oven at 180 °C for 20 minutes.
Preparing the butter and miso crumble:

In the meantime, crumble the 10 g of butter with your hands together with the 30 g of flour and a pinch of salt until it forms a crumbly mixture. Spread the crumble on a small baking tray and bake until golden brown, taking care not to burn it.

Carefully turn the tarte tatin out onto a plate. Place the crumble next to the tarte and add the buffalo ricotta, shaping it as desired with two tablespoons.
Decoration and presentation:
sprinkle with beetroot powder to add a hint of colour and a slight earthy note 
to the dish.
Note:
this tarte tatin offers an interesting combination of flavours. The sweetness of the Golden Delicious apple combines with the unique taste of leek and miso, while the crumble provides a pleasant crunch and the buffalo ricotta cheese adds a creamy note. Beet powder completes 
the dish with a touch of colour.