Whisk together eggs and oil. Pour cake mix into the bowl and fold in with a spatula.
Cover the bowl and chill in the fridge for one hour. Remove from the fridge and preheat the oven to 325F. Line a baking sheet with parchment paper.
Using a cookie scoop, scoop out 2 tbsp per cookie until you have 12 balls. Roll each into a tight ball. If desired, roll each ball in sugar.
Place each cookie dough on a baking sheet with lots of space between them - cook in 2 batches if needed. Bake for 12-14 minutes.
Remove from oven and cool completely on a wire rack. If desired, mix food dye into icing to make pink icing. Spread icing between two cookies to make cookie sandwiches.