First, prepare lemon syrup.
Wash the lemon well.
Slice its ends.
Slice the lemon thinly.
Place lemon slices in a saucepan with 2 cups water over medium high heat.
Bring to a boil, then reduce the heat to medium and let boil for 10 minutes.
Remove from heat and add granulated sugar.
Mix well and let cool completely. You can add ice to speed up the cooling process.
Strain the lemon syrup.
Add 2 cups cold water on the lemon in the strainer to get all the syrup out.
Add the strained fresh lemon juice.
Add more cold water about 6 cups (more or less to your liking). If you want the juice to be more sweet, then add less cold water.
Add milk, orange blossom water and vanilla powder.
Mix everything well.
Pour in a cup and enjoy.