Preheat oven (electric cooker: 175 °C/circulating air: 150 °C/gas: see manufacturer). Grease a springform pan (26 cm Ø) and dust with flour. Halve the avocados. Remove seeds. Remove the flesh with a spoon.
Mix with lime juice. Puree with a hand blender.
For the dough, whisk 200 g butter, 1 pinch of salt and 200 g sugar with the whisks of the mixer until foamy. First add the eggs one after the other, then half the avocado puree. Mix 50 g pistachios, 325 g flour and baking powder.
Quickly stir into the avocado-butter-sugar mixture. Smooth in the mould. Bake in a hot oven for 50-60 minutes (chopstick test), if necessary cover with aluminium foil after 45 minutes. Remove and let cool.
For the Cream Rest Avocado Puree, stir briefly. Stir cream cheese with 50 g icing sugar until smooth. Gradually stir into the avocado puree. Spread the cream on the cake just before serving. Decorate with green-white marshmallow flowers as desired.
For the sauce, peel and chop the kiwi. Puree with 1 tablespoon icing sugar and serve with it.