• Preheat the oven to 350 degrees Fahrenheit/ 180 degrees Celsius.
• Prepare springform: Butter it well all over. Sprinkle about 1 heaped tablespoon of flour in the springform. Turn and shake the springform to coat it all over with the flour. Turn the springform over the sink and pat it gently on the bottom to help remove the excess flour.

Spinach puree:

• Remove the stems if they are too thick. Wash the leaves in a colander and shake well to remove excess water.
• Blend in a food processor or blender until smooth. Scrape the walls of the kitchen gadget a few times in between.

Batter:

• Wet ingredients: Beat the egg, sugar, and vanilla extract until light and a bit fluffy. Add oil, lemon juice, and spinach puree and mix to combine.
• Dry ingredients: In another bowl, mix flour, baking powder, and salt. Sieve them over the egg mixture.
• Combine: Mix shortly to combine, don’t overmix. Pour the batter into the prepared springform.
• Bake for about 40 minutes or until a toothpick inserted in the middle of the cake comes out clean.
• Let cool in the pan for about 10 minutes. Release carefully and transfer to a wire rack to cool completely.

Frosting:

• Melt chocolate at bain-marie: Place finely chopped white chocolate in a waterproof bowl. Pour some water into a saucepan that can hold the bowl on top. Place the bowl with the white chocolate on top, but make sure that the bowl doesn't touch the water. Melt the chocolate slowly, stirring often. Set aside while you prepare the rest.
• Combine: Mix cream cheese shortly to make it softer. Add soft butter and mix well until pale and creamy. Slowly add melted chocolate, one tablespoon at a time, stirring well after each addition. Once you have incorporated all the chocolate, mix well until fluffy.

Assemble:

• Cut the cake horizontally into two layers.
• Fill cake: Place one layer on a platter. Spread ½ of the frosting on top. Cover with the second cake layer and pipe or spread the remaining cream cheese frosting on top.