- Preheat the oven to 170 degrees celcius and prepare a water bath (fill a tray larger than the cake tin with about 2 cm of hot water.
- Grease and line the bottom and sides of an 8x8 inch square tin.
- Bring 80ml of milk to boil, add Lavender and simmer for a minute or two. Strain off the lavender and put the milk back into the pot. (The recipe leaves the lavender in but I don't find it nice to eat so I prefer to remove them.) With heat still turned on, add butter to the milk and turn off heat when butter has melted. Leave the mixture to cool until not hot to the touch. (If the mixture is too hot, it cooks the eggs and flour when added into it, and batter curdles. It will be impossible to mix in with the egg whites if you did that.)
For a green tea variation, use 2 tbsp of green tea powder mixed with 2tbsp of hot water. Mix in with the 30ml of milk before adding to the warm batter. I did a marble green tea version, shown below.