Heat the oven to 350 degrees and line a baking sheet with parchment paper.

Stir the flour, baking soda, and salt together in a bowl and set it aside.

In a larger bowl, beat the softened butter and sugar until smooth and creamy.

Add the egg and vanilla extract to the butter mixture and beat until fully combined.

Mix in the green food coloring until the dough reaches a bright green shade.

Add the dry ingredients to the wet ingredients and stir until a soft dough forms.

Drop rounded tablespoons of dough onto the prepared baking sheet, spacing them a few inches apart.

Bake for 9 to 11 minutes until the edges look set but the centers still appear soft.

Remove the sheet from the oven and gently press candy eyes onto each warm cookie while they are still soft.

Let the cookies cool on the sheet for 5 minutes, then move them to a wire rack to finish cooling.