To make fruit topping, place all ingredients in a bowl. Gently stir to coat fruit in golden syrup. Set aside while making pancakes (standing time allows juices to release from fruit).
Set aside 150g ricotta in fridge for serving. Place remaining 150g ricotta in a medium bowl with egg yolks and golden syrup. Whisk to combine, then whisk in buttermilk and essence.
Sift flour and baking powder into a large bowl. Return any husks remaining in sieve to the bowl. Add oats. Make well in centre. Add ricotta mixture. Whisk to form a smooth, thick batter.
Using a clean wire, whisk or hand -held electric mixer, beat egg whites in a small bowl until soft peaks form. Fold into batter.
Heat a large, non-stick frying pan over a medium heat. Lightly grease with cooking oil. Spoon 2 heaped tablespoons of batter into pan to make an 8cm pancake. Repeat to make 2 more pancakes. Cook for 2-3 minutes, or until browned underneath. Turn pancakes and cook for a further 2 minutes, until other side is browned. Remove. Cover with foil to keep warm. Continue with remaining batter, re-greasing pan with a little cooking spray between batches, to make 12 pancakes altogether.
To serve, arrange pancakes in stacks of 3. Top with reserved ricotta, fruit topping and walnuts.