Take a blender jar, add ice cream scoops. Moreover, its not necessary that ice cream should be hard. Its okay to go with soft ones.
Furthermore, add milk and sugar to it.
Sugar quantity could be adjust more or less as per taste.
Next, add 1 teaspoon Vanilla Extract to it or you can add ½ teaspoon vanilla essence.
Blend it until it turns smooth.
Now pour it into tall glass, you can add some ice cubes if you prefer chilled milkshake.