Cake:

• 280g (2 cups) all-purpose flour
• 2 tsp baking powder
• 2 tsp baking soda
• 2 tsp ground cinnamon
• 2 tsp ground nutmeg
• 1 tsp kosher salt
• ¾ cup vegetable oil
• 250g (1 ¼ cups) granulated sugar
• 100g (½ cup packed) dark brown sugar
• 4 large eggs, room temperature
• 390g (4 cups, 5 carrots) shredded carrots
• 225g (¾ cup) crushed pineapple

Frosting:

• 115g (½ cup) cream cheese, softened
• 113.5g (½ cup, 1 stick) unsalted butter, softened
• 425g (3 ½ cups) icing sugar
• 2 tbsp (½ lemon) lemon juice
• ½ tsp pure vanilla extract

1. Place the oven rack in the middle of the oven.
2. Preheat the oven to 350°F.
3. Butter three 8-inch round cake pans.  Line the bottoms with parchment paper and dust the sides with flour.  Set aside.
4. Stir the flour, baking powder, baking soda, cinnamon, nutmeg and salt together in a small bowl.  Set the dry ingredients aside.
5. In the bowl of a stand mixer fitted with the paddle attachment, beat the granulated sugar, dark brown sugar and oil together on medium speed for 2 minutes.
6. Bring the speed down to low and add the eggs one at a time.
7. Gently fold the dry ingredients into the batter.  Be careful not to overmix!
8. Fold the pineapple and shredded carrots into the batter until incorporated.
9. Pour the batter evenly into the 3 prepared cake pans.
10. Bake for 25 minutes, or until a toothpick inserted in the center comes out clean.
11. Let the cakes cool completely in the pans on a wire rack.
12. Run a small offset spatula along the edges of the pan to help unmold the cakes.  
13. Flip the pans upside down.  Once the cakes are released from the pans, peel off the parchment paper.
14. For the frosting, beat the butter and cream cheese together in the bowl of a stand mixer fitted with the paddle attachment.
15. Add the vanilla and lemon juice, beating until combined.
16. Reduce the speed to low as you slowly incorporate the icing sugar, then bring the speed up to medium-high to beat the frosting until you reach an airy consistency.
17. Assembly: place the bottom layer of the cake on your serving platter.  Add ⅓ of the frosting and use an offset spatula to spread it evenly across the layer.  Repeat for cake layers 2 and 3. 
18. Slice the cake into 8 generous portions, or 12 more modest slices.
19. Store in an airtight container in the fridge for up to 3 days.