In a blender, add 1.5 cups cold milk, 2-3 large scoops of chocolate ice cream, 2-3 tbsp chocolate syrup (or 2 tbsp cocoa powder), and a dash of vanilla extract.
Blend on high speed for 45-75 seconds until smooth, thick, and creamy.
Pour into a tall glass.
Top generously with whipped cream, drizzle more chocolate syrup, and sprinkle chocolate shavings.
