- 1 cup whole milk
- 1 1/2 tablespoons white sugar
- 5 drops vanilla extract
- 15 ice cubes, or as needed
- 1 teaspoon salt
- Combine milk, sugar, and vanilla extract in a quart-size resealable bag; seal and shake.
- Fill a gallon-size resealable bag with ice cubes; add salt. Place the bag with milk mixture inside the bag of ice; seal and shake until milk mixture thickens, 5 to 8 minutes. Pour milkshake into a tall glass or cup.