Using a large bowl, add oil and sugar; mix until well combined.

Sift the remaining dry ingredients (flour, cinnamon, nutmeg, baking powder, baking soda, and salt) together. Add mixture to the oil and sugar; mix until well combined.

Add eggs; mix until just combined.

Add carrots, walnuts and raisins; mix until just combined. Set carrot cake batter aside.

Using a countertop or electric mixer, beat the cream cheese on medium speed until completely smooth (~3 minutes).

Add sugar and flour; mix well. (Tip: Don’t forget to scrape the bottom and sides of the mixing bowl to fully incorporate the sugar.)

Add eggs, egg yolk, sour cream and vanilla; mix fully.

Preheat oven to 350°F.

Grease and flour a 9” springform pan.

Pour half of carrot cake batter into pan; spread until smooth.

Drop about ⅓ of the cheesecake mixture in large dollops on top of the carrot cake. (Tip: Don’t swirl or spread the cheesecake. Just dollop!)

Pour remaining carrot cake batter over cheesecake dollops.

Finally, pour the remaining cheesecake mixture over the carrot cake. Spread top layer of cheesecake mixture so that it completely covers the carrot cake batter.

Bake at 350°F for 65-70 minutes, or until cheesecake portion of cake is just barely set. (Tip: After 40 minutes, place an aluminum foil tent over cake to prevent top from browning too much.)

Place cake on wire rack until completely cool.

Using an electric mixer, beat cream cheese and butter together until smooth.

Add the powdered sugar in ½ cup at a time, mixing after each addition.

Add sour cream and vanilla; mix until well combined.

Once cake has cooled, spread frosting evenly on top of cake.

{Optional} Garnish top of cake with chopped, toasted walnuts. (Tip: To toast chopped walnuts, bake at 350°F for 3-5 minutes, or until they begin to smell.)

Refrigerate cake until well chilled before slicing and serving.