Start by freezing 1 cup of whole milk for 3-4 hours.
Make the custard next. Stir together 2 tablespoon instant custard powder and ¼ cup of cold milk in a small bowl. Mix to make a lump free mixture.
Transfer the remaining milk in a medium size pot and keep it over medium heat.
Slowly add the slurry to the pot and cook on medium heat until the custard thickens. Keep stirring continuously to avoid the formation of lumps.
Note – To check if the custard is cooked, dip your spoon into it and then draw a finger through the coated spoon. Does it wipe clean, leaving an open space? Then your custard is done.
Once it has thickened, remove the pot from the heat and transfer it to a bowl.
Cover the bowl with a cling film to avoid the formation of a cream layer on top. Refrigerate for 30 minutes.
Now add the chilled custard, frozen milk, 2 tablespoon sugar, and ½ teaspoon vanilla extract to the medium jar of a blender and blend until smooth.
Pour the milkshake into 2 tall serving glasses.
Add some soaked basil seeds to each glass and top the glasses with vanilla ice cream. Garnish with chocolate syrup and mint leaves. Serve chilled.
Freezing the milk makes the milkshake very creamy. Do not freeze it for too long otherwise, it will be difficult to blend.You can also make a rose-flavored custard milkshake by adding some roohafza along with other ingredients.To make it even more special, add in some cashew or almond powder while blending.