Preheat the oven to 350 F (180 C)
Stir together the flax, cocoa, soda and salt in a bowl.
In a jug, whisk together the vanilla, honey, egg, pumpkin and cashew butter with a fork. Pour into the dry ingredients and mix until well combined.
Pour into a greased, lined 1lb loaf pan (line it with a bit of an overhang so you can lift the cake out easily). Scatter over the chocolate chips and push them into the batter. Bake for 40-50 minutes until the cake doesn't wobble when you shake the pan (the skewer test doesn't really work with this).
Stir together the powdered raw sugar and cocoa powder, then stir in almond milk until you get quite a thick glaze (just start with a teaspoon first and add more as needed). Pour over the hot cake and spread out evenly using the back of a spoon.