Preheat oven to 350°F. Grease and flour a 9-inch round cake pan, set aside.
In a medium bowl, whisk or sift together the flour, baking powder, ground cinnamon, salt, baking soda, nutmeg, and all-spice. Set aside.
In a large mixing bowl, whisk together the sugar, oil, buttermilk, lemon juice and vanilla until well combined. Stir in the eggs, carrots, and zucchini whisking rapidly until smooth. Add the dry ingredients, and fold until just combined, and no flour remains in the batter. Do not over mix at this stage. Pour the batter into the prepared pan and bake until golden brown and a toothpick, inserted in the middle, comes out clean, about 30 to 35 minutes. Remove from the oven and let cool for 10 minutes in the pan before removing the cake onto a wire rack to cool completely.
To make the frosting, beat the cream cheese and butter on high, until light and fluffy. Beat in the honey and then add the powdered sugar with a pinch of salt, beating on high to combine. Whisk in the milk until you get a smooth spreadable frosting.
To make the marzipan carrots, wearing gloves, place a small amount of gel food coloring into the marzipan and knead with your hands until it's evenly colored. Divide into 7 to 8 even pieces, and then shape into carrots. Use a toothpick to create "lines" on the surface of each carrot. Place a small sprig of mint on the top of each.
Spread the cooled cake with the frosting and then sprinkle with chopped pistachios. Then stick the carrots on top of the frosting, to create a garden. Cut and serve or place in the fridge until ready to eat. Allow the cake to come to room temperature before serving. Enjoy!