Heat the oil in a large saucepan with a tightly fitting lid. Add the corn kernels and put the lid on. Give the pan a gentle shake listen for the popping to start, then stop. Once it’s stopped, turn off the heat, stir through the matcha powder and put to one side.
Line a large tray with baking paper. Melt the chocolate in a glass bowl over simmering water, make sure the bowl isn’t touching the water. Once melted, pour it over the green popcorn and stir it through - stopping before it’s fully mixed in so that you have a mix of colours of green and white. Spread it out on the baking paper then leave it to set in the fridge. Once set, break it up into bite-sized pieces and serve.