Preheat oven to 350°F (175°C) and line two baking sheets with parchment paper.

In a large bowl, cream together softened butter, granulated sugar, and brown sugar until light and fluffy.

Beat in eggs one at a time followed by vanilla until well combined.

In another bowl, whisk together flour, baking soda, and salt; gradually mix into wet ingredients until just combined.

Divide dough into four portions and mix different food coloring into each portion to create vibrant colors.

Take small pieces from each colored dough and place randomly onto prepared baking sheets; swirl with a toothpick for tie-dye effect without overmixing.

Bake for 10-12 minutes or until edges are golden and centers are soft; let cool on baking sheets briefly before transferring to wire racks.