Line a cake tin with baking paper.

Heat the oven to 170°C.

Separate 5 of the eggs, putting the whites and the yolks into two different bowls.

To the bowl with the yolks, add the whole 6th egg, 250 g of the sugar and the grated zest of all 3 oranges. Beat until the sugar dissolves and the mixture becomes foamy.

Add the almond flour and fold it in with a spatula until you get a dense, crumbly batter.

Whisk the egg whites separately until they form stiff peaks.

Gently fold the whipped whites into the yolk mixture a little at a time, mixing well but gently until fully incorporated and keeping it as fluffy as possible. Transfer the batter to the lined cake tin and bake for 45 minutes, or until golden around the edges.

Meanwhile, prepare the syrup.

In a saucepan, combine the remaining 50 g of sugar, the juice of all 3 oranges and the water.

Bring to a boil over low heat, then remove from the heat and stir well to dissolve the sugar. Add the sage leaves and let the syrup infuse until the cake is ready to come out of the oven.

As soon as the cake comes out of the oven, prick it all over with a toothpick while it is still warm. Pour the infused syrup over the top and set aside until it cools completely.

Decorate with sage leaves and/or orange slices.