Inspired by Holy_Cowie's suggestion, this is a cooking recipe that provides a 20% chance to double the reward in the Exchange Centre and last for 5 minutes. Recipe is as follows:
200 coal
100 onion
100 pepper
100 tomatoes
30 eggs
7 herbs
2 salt
3 sunflower oil - so it doesn't stick to the pan
1 pie pan
Cooking time: 30 minutes
Thanks for reading!