Blend 1½ cups rolled oats into fine flour and transfer to a bowl

Chop walnuts finely and add to the oat flour

Sprinkle ¾ tbsp ground cinnamon into the oat flour mixture and stir to combine

Grate 2 carrots on a fine grater and place in a separate bowl

Peel and grate 1 medium sweet apple on a fine grater

Add grated apple to the carrots and gently fold together with a spatula

Add 4½ tbsp Greek yogurt or sour cream to the carrot-apple mixture and mix until combined

In a separate bowl, crack 2 room-temperature eggs and add a pinch of salt

Beat the eggs lightly with a fork until yolks and whites are combined

Pour the beaten eggs into the carrot-apple bowl and stir until blended

Add 3–3½ tbsp honey and mix until fully incorporated

Zest 1 lemon (yellow layer only) and add to the mixture

Soak 1 tbsp raisins in hot water for 10 minutes, then add to the batter

Add 1½ tbsp melted coconut oil or vegetable oil and stir

Transfer the wet mixture into the bowl with oat flour and mix until soft, spreadable batter forms

Add 1 tsp baking soda and pour 1½ tbsp lemon juice on top, then stir to combine

Butter the bottom and sides of an 8-inch round springform pan and line with parchment paper

Transfer the batter into the prepared pan and smooth evenly

Combine 3 tbsp rolled oats, 1 tbsp melted coconut oil, 1 tsp ground cinnamon, and 1 tbsp honey for the topping

Spoon the oat topping over the batter and smooth evenly across the surface

Bake at 350°F (180°C) for 50–55 minutes until golden brown

Cool the cake for 10–15 minutes, then run a silicone spatula around the edges to loosen

Release the springform ring and transfer the cake to a wire rack to cool completely

Peel off the parchment paper once cooled

For the frosting: combine 9 oz cream cheese or ricotta in a clean bowl

Add 2 tbsp Greek yogurt and ¼ tsp vanilla extract to the cream cheese

Gently fold everything together until smooth and well combined

Add a splash of lemon juice and a touch of honey, then fold together again

Spread the frosting over the top and sides of the cooled cake

Sprinkle chopped walnuts over the frosting for garnish

Refrigerate the cake for at least 30 minutes before serving