Cooking oil spray, to grease 2 cups plain flour
2 tsp bicarbonate of soda
2 tsp baking powder
500g carrots, peeled, coarsely grated
3⁄4 cup brown sugar, firmly packed
100g walnuts, finely chopped, plus extra 1 cup, finely chopped, plus extra 1⁄2 cup, roughly chopped
3⁄4 cup extra virgin olive oil light in flavour
3 free-range eggs
1 ripe avocado, mashed
Finely grated zest of 3 lemons
1⁄4 cup lemon juice
1 tsp vanilla extract
125g blueberries, to serve
Blueberry leaves from your garden, to garnish (do not eat, decoration only)
Lemon ricotta frosting
250g fresh ricotta
50g butter, chopped, softened
1⁄2 cup icing sugar mixture
Finely grated zest of 1 lemon
Preheat oven to 160°C fan- forced (180°C conventional). Grease a 22cm round loose-bottomed cake tin with cooking oil then line base and sides with baking paper.
Sift flour, bicarb, baking powder into a large bowl. Add grated carrot, brown sugar and walnuts, then stir until just combined.
Put oil, eggs, avocado, lemon zest and juice, and vanilla in a large bowl and whisk until just combined. Pour into carrot mixture and stir until just combined.
Spoon batter into prepared tin, and smooth with the back of a spoon. Bake for 1 hour 10 minutes or until cooked when tested with a skewer. Set aside in tin for 15 minutes to cool then turn out onto a wire rack to cool completely.
Meanwhile, to make lemon ricotta frosting, put all ingredients in the bowl of a food processor and process until smooth.
Cover side of cooled cake with a thin layer of frosting, and spread remaining on top. Firmly press extra finely chopped walnuts around side of cake so they adhere to icing. Garnish top of cake with blueberries, extra roughly chopped walnuts and blueberry leaves (for decoration only, do not eat). Serve.