01 - Preheat oven to 350°F. Line an 8x8-inch baking pan with parchment paper, leaving overhang for easy removal.
02 - In a medium bowl, whisk together flour, baking powder, baking soda, salt, cinnamon, and nutmeg until well combined.
03 - In a large bowl, whisk brown sugar, granulated sugar, eggs, oil, and vanilla until smooth and incorporated.
04 - Fold grated carrots, drained pineapple, and nuts into the wet mixture until evenly distributed.
05 - Add dry ingredients to wet mixture; stir until just combined. Set aside.
06 - In a separate bowl, beat cream cheese until smooth. Add sugar, egg, and vanilla; blend until creamy and lump-free.
07 - Spread 2/3 of carrot cake batter into prepared pan. Pour cream cheese mixture evenly over top. Dollop remaining carrot batter over cream cheese layer.
08 - Use a knife or skewer to gently swirl the batters together for a marbled effect. Do not overmix.
09 - Bake for 38-42 minutes, or until a toothpick inserted in the center comes out mostly clean.
10 - Cool completely in pan. Refrigerate for 2 hours for easier slicing. Cut into 16 bars and serve.