Gather all ingredients and prep them by cutting brownies and softening ice cream for easier blending.
Layer milk, brownie chunks, chocolate syrup, vanilla, and ice cream in the blender to ensure smooth blending.
Blend on low to break brownies, then high until thick, smooth, and creamy, adjusting milk or ice cream as needed.
Taste the milkshake and adjust flavor by adding extra chocolate syrup or a pinch of salt to balance sweetness.
Pour into chilled glasses, top with whipped cream, brownie chunks, and chocolate drizzle, and serve immediately.