Blitz the ice cream, milk and vanilla extract in a blender until combined and creamy.
Pour into a large jug.
Dip the rims of four glasses in the melted white chocolate, then some sprinkles, if you like.
Leave to set slightly, then divide the milkshake between the glasses. You can customise your shake with different toppings, such as mini cookies, marshmallows, pretzels, sweets, squirty cream, and your favorite Stik-O wafer sticks.
