Using a lidded heavy bottomed sauce pan, heat a 1tsp flavourless oil over a medium to high heat, add the corn and place the lid on top. Jiggle the pan over the heat until the corn starts popping. Make sure you don’t remove the lid until all the corn has popped otherwise it will go everywhere! Once popped, pour into a large bowl
Using a large saucepan, melt together the sugar, water and dairy-free butter. Once the sugar crystals have melted, increase the heat until you reach 180 degrees Centigrade.
Immediately turn off the heat and stir in the vanilla and bicarb. The bicarb will make the caramel puff up so watch out.
Pour the popcorn into the caramel and stir until all the pieces are coated. Tip onto a silicone baking mat, or some baking parchment and leave to set.
Once cool and set, break into smaller pieces and place in an airtight container.