Method

• Preheat the oven to 170°C. Line a 22cm square baking tin with baking parchment.
• To make the carrot cake: beat together the butter, brown sugar, eggs and vanilla in a large bowl until combined. Add the flour, baking powder, bicarbonate soda, salt, mixed spice and cinnamon, whisking until just combined. Stir in the grated carrots.
• To make the cheesecake mixture: In a mixing bowl, whisk together the cream cheese, sugar, lemon zest and flour until combined, about three minutes. Add the egg, vanilla and whisk once more until the mixture is smooth.
• To assemble: spread about two thirds of the carrot cake batter into the prepared tin in an even layer. Now pour over two thirds of the cheesecake mixture, then blob spoonfuls of the remaining carrot cake mixture on to the cheesecake layer. Pour over the remaining cheesecake mixture.
• Bake for 45-55 minutes, cover the cake with foil halfway through cooking to prevent the top from browning. Cool the cake in the tin, then refrigerate for at least three hours.
• For the icing: whisk the butter, icing sugar, vanilla and 3 tablespoons water, until smooth. If needed, thin with additional water. Drizzle the icing over the squares
• Leave to set for about an hour before cutting into squares.
• The squares can keep chilled in the fridge for up to five days.
• If required, garnish with finely chopped pistachio nuts and edible rose petals.