Then mix like this

1. Preheat oven to 170C. Line two baking trays with baking paper.
2. Place butter into bowl. Speed 4 until softened.
3. Add vanilla and condensed milk. Speed 5 / 1 minute.
4. Add half of the flour. Speed 5 / 15 seconds.
5. Add the remaining flour. Speed 5 until combined. Add additional flour if your mixture is too wet until it comes together.
6. Place sprinkles into a small bowl.
7. Roll dough into a small ball about the size of a bliss ball. This will make 50 biscuits.
8. Flatten slightly and place into the sprinkles to coat one side.
9. Place biscuits onto tray, sprinkle side up.
10. Bake for 10-12 minutes or until slightly golden.
11. Cool on a wire rack.

Or cook like this

1. Preheat oven to 170C. Line two baking trays with baking paper.
2. Place butter into bowl. Beat with an electric mixer until softened.
3. Add vanilla and condensed milk. Beat on medium speed for 1 minute.
4. Add half of the flour. Using a wooden spoon mix to combine.
5. Add the remaining flour. Mix to fully combine.
6. Place sprinkles into a small bowl.
7. Roll dough into a small ball about the size of a bliss ball. This will make 50 biscuits.
8. Flatten slightly and place into the sprinkles to coat one side.
9. Place biscuits onto tray, sprinkle side up.
10. Bake for 10-12 minutes or until slightly golden.
11. Cool on a wire rack.