Preheat your oven to 170°C (340°F). Lightly grease a springform pan and line the bottom with parchment paper. This helps prevent sticking and makes it easier to release the cake later.

In a medium bowl, whisk together flour, baking soda, baking powder, cinnamon, nutmeg, and salt.

In a separate large bowl, whisk eggs, granulated sugar, brown sugar, oil, and vanilla extract until smooth and slightly thickened. Fold in the grated carrots and walnuts if using.

Gradually add the dry ingredients into the wet mixture and gently fold until just combined. Avoid overmixing to keep the cake soft.

In another bowl, beat the softened cream cheese and sugar until completely smooth and lump-free. Add eggs one at a time, mixing gently after each addition. Stir in sour cream and vanilla extract until creamy and silky.

Pour the carrot cake batter evenly into the prepared pan. Carefully pour the cheesecake mixture over the top. If you like, use a knife to gently swirl the layers for a marbled effect.

Place the pan in the oven and bake for 55–60 minutes. The edges should look set, while the center should still have a slight jiggle. Avoid overbaking, as this can dry out the cheesecake.

Turn off the oven and leave the door slightly open. Let the cake cool inside for about 30 minutes. This helps prevent cracks by allowing gradual cooling.

Transfer the cake to the refrigerator and chill for at least 4 hours, preferably overnight. This step is essential for achieving the perfect texture.

Slice with a sharp knife, wiping the blade between cuts for clean edges. Serve chilled or slightly at room temperature.