• Toast the nuts Spread the walnuts or pecans in a dry skillet over medium heat. Toast for 5–8 minutes, stirring frequently, until fragrant and lightly golden. Let cool completely then chop roughly. Set aside.
• Preheat oven to 350°F (175°C). Butter a 9-inch springform pan, line the bottom with a round of parchment paper, then butter the parchment.

Cheesecake Layer

• Make the cheesecake mixture. In a large bowl, beat the cream cheese with both sugars on low speed until completely smooth with no lumps, about 2 minutes. Add the sour cream, tahini, and vanilla and mix until just combined. Add the eggs one at a time, mixing just until incorporated after each. Stir in the flour and salt. Set aside.

Carrot Cake Layer

• Make the carrot cake mixture. In a medium bowl, whisk to combine the flour, baking soda, baking powder, salt, cinnamon, ginger, nutmeg, allspice, cardamom, and black pepper.
• In a separate large bowl, combine the oil, applesauce, both sugars, eggs, and vanilla. Whisk by hand for about 1 minute until no lumps of brown sugar remain. Add the dry ingredients into the wet ingredients and fold with a spatula until just blended. Do not overmix. Fold in the carrots and nuts, if using.
• Layer the batters. Pour about 1½ cups of carrot cake batter into the prepared pan and spread into an even layer. Drop about one third of the cheesecake mixture over the carrot cake batter in spoonfuls. Don't spread or swirl the batters. Use a large spoon to spoon the remaining carrot cake batter gently on top. Use a large spoon to evenly spoon the rest of the cheesecake mixture over everything slowly and evenly overtop.
• Bake. Bake for 40 minutes, then loosely tent the top with foil, keeping it from touching the surface. Continue baking for another 20–25 minutes. The cake is done when the center has only a very slight jiggle.

  I don't recommend checking for doneness by inserting a toothpick in the middle because the toothpick might not come out completely clean (you'd probably see some cheesecake on it which is fine.
• Cool and chill. Cool on a wire rack for 1 hour at room temperature, then cover with foil and refrigerate for at least 6 hours or overnight. Do not remove the springform collar until the cake has chilled for the full time.

Decorate

• Make the honey labneh topping. Blot away or pour off any pooled liquid on the surface of the labneh. In a medium bowl, stir together the labneh, honey, vanilla, and salt until smooth. Start with 2½ tablespoons of honey, taste, and add another ½ tablespoon if you'd like it sweeter.

  If you'd like to use sour cream in place of labneh: Sour cream is thinner than labneh and won't set up the same. For this reason, I recommend using ½ cup sour cream + 1-1½ tablespoons honey + ¼ teaspoon vanilla and no salt.
• Spread the honey labneh over the chilled cake. Scatter the crumbled halva (or chopped nuts) generously over the top. Remove the springform collar and slice with a long sharp knife wiped clean between each cut.