Creating the Carrot Cake Roll with Cream Cheese Frosting Filling can be straightforward if you follow these steps:

1. Preheat the Oven: Start by preheating your oven to 375°F (190°C). Prepare a 15×10-inch jelly roll pan by lining it with parchment paper and greasing it lightly.

2. Mix the Wet Ingredients: In a large mixing bowl, beat the eggs with granulated sugar until the mixture is light and fluffy. Add the vanilla extract and grated carrots, and mix until evenly combined.

3. Combine Dry Ingredients: In a separate bowl, whisk together the ground cinnamon, ground nutmeg, baking powder, baking soda, and flour.

4. Combine Wet and Dry Mixtures: Gradually fold the dry mixture into the wet ingredients, stirring gently until just combined. If you’re adding nuts, fold them in at this point.

5. Spread the Batter: Pour the batter into the prepared jelly roll pan, spreading it evenly to the edges with a spatula.

6. Bake: Place the pan in the preheated oven and bake for 15-20 minutes, or until the cake springs back when lightly touched.

7. Cool and Roll: Once baked, remove the cake from the oven. Place a clean kitchen towel over the top, and carefully invert the cake onto the towel. Gently peel off the parchment paper, then roll the cake tightly, along with the towel, starting from the short end. Allow it to cool completely.

8. Prepare the Frosting: While the cake cools, prepare the cream cheese frosting. In a medium bowl, beat the softened cream cheese and butter together with an electric mixer until smooth. Gradually add the powdered sugar, mixing until light and fluffy. Add vanilla extract and a pinch of salt, then mix until combined.

9. Unroll the Cake: Once cooled, gently unroll the cake from the towel. Spread a generous layer of cream cheese frosting evenly over the surface of the cake.

10. Roll it Up Again: Carefully reroll the cake without the towel, making sure to keep it tight. Place the seam side down on a serving platter.

11. Frost the Outside (Optional): If desired, apply a thin layer of frosting over the outside of the cake roll for a polished finish. Top it with extra grated carrots or nuts for decoration.