Preheat oven to 350 degrees F. You will need 2 baking sheets, but do not line them with parchment paper or silicone baking mats.
In a large mixing bowl add softened butter and sugar, mixing with a hand mixer until smooth. Add eggs and vanilla and continue to mix until fluffy.
Add flour and salt into a large bowl and mix again until cookie dough forms.
Separate the cookie dough into 6 balls. On a floured surface, roll each dough ball out into a long rope, about the width of your index finger. Cut dough into 1 inch pieces, and gently roll in a shallow bowl of rainbow sprinkles. Place cookies on baking sheets.
Bake for 8-10 minutes, or until golden brown on bottom. Remove from oven and allow to cool.