Put oil in a blender and keep adding the spinach until it has been mixed thoroughly.
In a larger bowl mix eggs, buttermilk, sugar and add the spinach mixed with oil. Finally, sift the flour (mixed with baking soda and salt) into the mix and blend everything nice and smooth.
Pour the dough into a 20 cm round mold, line the bottom with baking paper and bake at 350 F for about 45-50 minutes (test with a skewer to see if it is done).
Let the cake cool down, cut off the top and save it on the side for later.
Whip 100 ml heavy cream with 250 g of mascarpone, 10 g of vanilla sugar and 40 g of powdered sugar. First slowly, for about a minute and then whip using the highest speed for about 2 minutes. Slow down the blender again and mix in 125 g of Farmer cheese (adding it by spoons).
Put the frosting on the cooled cake.
Crumble the cut off top of the cake and sprinkle the crumbs over the frosting.