Add the Mastiha tears to a small food processor along with 2 tablespoons of the sugar. And blend until the tears turn into fine powder just like the sugar. Set aside.
Take one cup of milk out of the 780 grams and add it to a small saucepan together with the Salep. Heat over medium-low heat stirring with a whisk until Salep dissolves completely. For this to happen it needs to get to a point where the milk gets steamy hot. Don't let it boil though as we don't want it to thicken yet.
In a medium-sized cooking pot add the remaining milk, the whipping cream, the sugar, the Mastiha and sugar mix, the Salep and milk mixture, and salt.
Heat over medium-low heat stirring occasionally with a whisk. If your stove is too strong you may want to keep the heat to low. Keep an eye on the pot and heat the mixture for about 30 to 40 minutes. It will slowly start to become slightly thicker than its original form looking more creamy but runny. And on the surface, it will form lots of foam/froth which is called the Kaimaki. Keep stirring occasionally and keep an eye on the pot during the whole process as it can easily get very frothy and spill out of the pot. When little bubbles start to form on the top and it starts simmering turn the heat off and transfer the mixture to a mixing bowl letting it cool down to room temperature.
When the mixture has cooled (which takes about 2 hours) stir in the Mastiha liquor or Rum, as well as the rose water.
Cover bowl with plastic wrap and place in the fridge for about 3 hours to cool.
Then you can either transfer mixture to the ice cream machine or make the Kaimaki ice cream using an electric hand mixer.
To make the ice cream using an electric hand mixer first place the mixture in a mixing bowl with a lid. A stainless steel bowl would be ideal as it will distribute temperature and cool the ice cream quicker and more evenly.
Place the bowl in the freezer for one hour. Then remove it from the freezer and place the whisk attachment on your electric hand mixer. Beat over medium speed for 2 minutes working all around mixing well the mixture that's all around the sides of the bowl (as this is where it is starting to freeze).
Turn the mixer off, put the lid on the bowl and place it back in the freezer.
After 1 hour, repeat the above process. Beat for 2 minutes and then place back in the freezer.
Repeat this process of mixing and freezing a total of 4-5 times. Until the texture of the mixture looks like a thick cream.
Then freeze for 3-4 hours more before serving.
Don't forget to get the ice cream out of the freezer 10 minutes before serving.
Serve the Kaimaki ice cream Greek-style topped with sour cherry preserves in syrup. Or any other red berry preserves such as raspberries, blueberries, etc.