For a 13''x18''/33x45cm baking tray lined with a greased parchment paper or silicone mat.
In the food processor, turn walnuts into meal. Add four, baking powder, baking soda, cinnamon and salt. Mix to combine; set aside. Peel, wash and shred carrots. Break them down further using the blade of the food processor. Grate shredded carrots along with the ginger (just grate, do not not puree). In a large saucepan, cook down carrot and orange juice for about 15 minutes, or until moisture is gone. (Pre-cooked carrots instead of raw produces a really moist cake that is better the day after it is made). Add pineapple*. Meanwhile, in the stand mixer fitted with the whisk attachment beat eggs and sugars on high speed for 10 minutes, or until pale and fluffy. Transfer mixture to a large bowl. With a rubber spatula, add oil slowly – followed by the dry ingredients, and carrot mixture. Spread batter evenly onto the prepared baking tray.
*For better redistribution, pineapple can be added once the carrot sponge batter is spread. Also, pineapple can be flambéed with dark rum prior to add to the mixture. To do so, in a hot pan sear pineapple dices along with a tablespoon of brown sugar on high heat. Flambé with 2 tablespoons (30g) black spiced rum.

Preheat oven to 375ºF/180ºC. Bake carrot sponge for about 15 minutes. Let cool and freeze. Remove from sheet tray and cut into 4 rectangles. Keep refrigerated.

Combine sugar and agar agar. Reduce orange and carrot juice by half (100g). Add sugar-agar mixture. Mix well and cook for 2 minutes. Transfer to a small container lined with plastic wrap. chill and cut into small cubes. Jelly can be kept frozen for later use.

Spread frosting on cooled sponge, repeat until done. Finish cake in a fashion way using a medium size open star pipping tip. Freeze carrot cake for a couple of hours or until firm enough to trim off edges and cut. Decorate with orange-carrot jelly cubes. Top with real mini carrots if desired. To prepare them: peel and wash. Cook mini carrots in some orange juice and a couple of tablespoons sugar for about 20 minutes, or until just tender. Drain and chill. Reduce remaining juice and serve with the cake. Cake tastes best a day after. Keep refrigerated for up to 3 days or freeze well wrapped for a couple of months. Enjoy!