Preheat your oven to 180C / 350F / Gas mark 4 and line a 9x9 inch square tin with baking parchment, then place to one side.
If like me you are using mint matchmakers for you mint chocolate chips then either break them up by hand or cut them up into small chocolate chip size pieces.
In a large mixing bowl add in the flour, white chocolate drinking powder, both sugars and mix everything together.
Pour in the vegetable oil, eggs and vanilla extract. Mix everything until just combined.
Gently fold in your mint chocolate chips.
Pour the batter into your prepared pan and pop it in the middle of your preheated oven.
After 20 minutes, check on your blondie. You are looking for the edges to be set but the middle to have a very slight wobble. If it is still too runny leave in the oven for another 5 minutes.
Once baked take the pan out of your oven and leave to fully cool down to room temperature.
Once cool, take the blondie out of the pan and peel of any remaining parchment paper, place on a flat surface and cut into 12 squares.
These will keep at room temperature in an airtight container for up to 5 days.