1. Pulse your GF digestives and pistachios in a food processor until the digestives are a crumb but some small chunks of pistachio remain.
2. Melt the vegan butter, I melted mine in a bowl over a pan of boiling water. Once melted, remove the bowl from the heat and stir in the digestive crumbs and the cocoa powder.
3. Tip the mixture into your dish (I used an 8inch spring base cake tin) and press firmly down into the base to create an even layer. Chill in the fridge for 1 hour. After 30 minutes, start preparing the custard.
4. Bring the milk to a boil, then add in the orange oil
5. Then add 50g caster sugar and 4.5 tbsp of corn starch.
6. Transfer the mixture to a heat-resistant blender and blend until you get a nice smooth texture. Pour back into the pan, lower the heat and cook for another 10 minutes until it thickens. It may take less time, so watch closely.
7. When the base is ready to be removed from the fridge, pour the custard over the top evenly. As the dish is cold, it’s likely to set quickly so try to pour evenly. Add some pistachio kernels and/ or chocolate chips to the top now or use later as garnish.
8. Chill in the fridge for a further 30 minutes to allow it to fully set.

Serve and enjoy!