Preheat the oven to 175°C and line a loaf pan with parchment paper.
Combine all the cinnamon swirl ingredients until you get a smooth, thick paste.
In a large bowl, whisk together the oil, granulated sugar, brown sugar, eggs and vanilla. Stir in the sour cream and buttermilk.
In a separate bowl, mix the flour, baking soda, baking powder, cinnamon, nutmeg, ginger and salt. Fold the dry ingredients into the wet mixture, then gently stir in the grated carrots. Avoid overmixing.
Spread half of the batter into the prepared pan. Spoon over half of the cinnamon mixture and lightly swirl with a knife. Repeat with the remaining batter and cinnamon mixture.
Bake for 50–60 minutes, or until a toothpick inserted into the center comes out with a few moist crumbs. Let the cake cool completely.
Brown the butter until golden and fragrant, then let it cool slightly. Beat it together with the cream cheese and powdered sugar until smooth.
Warm the honey in a small pan, add the walnuts and toss until evenly coated and lightly caramelized. Finish with a pinch of salt and let cool.
Frost the cooled cake, top with the honey walnuts and enjoy!
