Preheat the oven to 180°C/Gas Mark 6. Lightly oil a 7-inch cake tin and dust with flour –shake out any excess flour.
To prepare the cake batter, place the gluten-free flour and ground almonds into a large bowl.
Add the pistachios to a food processor and blitz to a heavy crumb consistency. Add the pistachio crumbs to the flour and almonds. Add the baking powder, cinnamon, cardamom and a pinch of salt. Mix together well to combine.
Add the ground flax to a small bowl with the warm water. Stir together to combine, creating a flax ‘egg’. Set aside whilst you prepare the rest of the cake.
Cream the coconut oil and coconut sugar together in a mixing bowl or food processor. Add in the flax egg, vanilla extract, rose water and lemon juice. Mix together until smooth.
Slowly drizzle the tea or water into the wet ingredients a little at a time, stirring until smooth and well combined.
Add the wet ingredients into the dry ingredients and beat together well until smooth.
Spoon the cake batter into the lined cake tin and level with the spatula.
Transfer the cake to the oven for 35 minutes or until golden brown all over, cooked through and a skewer comes out clean.
Whilst the cake is cooking, whisk together the maple syrup and lemon juice.
Once the cake is cooked but still warm, drizzle over the lemon juice and maple syrup mix then scatter over the crushed pistachios and rose petals. Serve warm.