Pumpkin, carrot and walnut with cashew orange frosting

I took this recipe form Henrietta Inman book Clean Cakes and I can't recommend more this amazing book.

Ingredients

• Frosting
• 200g cashew nuts (about 260g soaked wet)
• 130ml of almond milk
• 80g clear raw honey
• 1/4 vanilla pod or vanilla escence
• Finely grated zest and 4tsp juice of 1/2 lemon
• Finely grated zest of 1 orange
• Pinch of salt
• 140g coconut oil, melted
• ---------------------------------------------------------------------
• Pumpkin Cake
• 90 g walnuts
• 70 g teff flour (or plain for a non gluten free version)
• 70 g brown rice flour
• 15 g arrowroot
• 3/4 tsp salt
• 1 tsp bicarbonate of soda
• 1 1/2 tsp mixed spice
• 1 1/2 tsp ground cinnamon
• 120 g Palmyra nectar powder (or light brown sugar)

Directions

1. Preheat the oven to 170C/325F
2. First make the frosting because it needs to be in the fridge for about 8hs. If you are in a hurry you can put is in the freezer (it won't ice)
3. Soak 200g of cashew nuts overnight or boil them for 4 minutes.
4. Put the soaked cashew nuts with the almond milk in a mixer and mix until completely smooth and silky.
5. Add honey, vanilla, lemon juice, orange and lemon zest and a pinch of salt and mix very well.
6. Add the melted (not hot) coconut oil to the mix and continue mixing.
7. On a baking try, lightly toast the walnuts for 5-8 minutes, until just beginning to color, leave to cool then chop into small pea-size pieces.
8. Grease an 18-20 cm (7-8 inch) loose-bottomed cake tin with oil and line the base with baking parchment.
9. In a large bowl, mix together all the dry ingredients (flour, arrowroot, baking soda, spices, sugar, sultanas and walnuts)
10. In another bowl mix the oil, pumpkin pure, grated carrot, orange zest and eggs (you can use ground flex seeds activated with water to substitute the eggs).
11. Fold the wet mix into the dry mix.
12. Pour the mix into the prepared tin and bake for 35-40 minutes rotating if need it. When cool, cut in half and fill with half the cashew orange frosting spreading the remainder on top. If the frosting it is too runny put in the freezer for 10 minutes.