In a large mixing bowl, whisk together the flour, baking soda, and salt. Set aside.

In a stand mixer, whisk the sugar into the melted butter. Let the mixture stand for a few minutes until it is lukewarm.

Beat in the eggs and vanilla.

Add the dry ingredients to the wet ingredients, and mix until combined.

Separate the dough into two equal parts, placing each half into separate bowls.

To one bowl, add the green gel food coloring, and to the other bowl, add the purple. Mix each well, until the food coloring is evenly distributed and no longer streaky.

Chill the dough for 15-30 minutes in the freezer.

On a floured surface, roll each batch of chilled dough out (separately) into ⅛ -¼-inch rectangles.

Using a spatula, carefully place the purple dough rectangle on top of the green dough rectangle, and roll into a cylinder.

Wrap the dough cylinder in plastic wrap, and chill in the freezer for 30 minutes- 1 hour (or in the refrigerator overnight.)

When ready to bake, preheat the oven to 350 degrees F, and line a baking sheet with parchment paper.

When the dough is chilled, slice ¼-inch disks from the cylinder. Place each disk onto the prepared cookie sheet, and bake at 350 degrees F for 10 minutes.

Let the cookies cool completely before decorating.

Using the black edible marker, make two circles slightly larger than the candy eye sprinkles.

Dab a small amount of the premade icing to the back of candy eyes, and place them to the center of each circle. Allow the icing to set before stacking.