Preheat the oven to 350 degrees. Prepare a 9x13 baking dish with non-stick cooking spray.
In a medium bowl, whisk together the flour, baking powder, baking soda, and salt.
In a large mixing bowl, beat the butter until fluffy. Slowly add the sugar and beat until completely incorporated. Add the vanilla and eggs, beating after each egg is added.
To the mixture, add the flour in ½ cup increments, alternating each addition with buttermilk. Blend just until mixed. Do not overbeat.
If desired, add yellow food coloring and stir until combined.
Pour the cake batter into the prepared 9x13 baking dish.
Place in the oven and bake for 40 to 45 minutes or until a toothpick inserted in the middle returns clean.
Allow the cake to cool on a wire rack to room temperature.
Meanwhile, place ¾ cup candy corn and water into a saucepan and cook over medium heat, stirring occasionally until the candy corn has melted. Bring the mixture to a boil and boil for 1 minutes. Remove from heat and allow to cool slightly.
Using a bamboo skewer, poke holes into the cake. Pour the candy corn syrup over the cake.
Spread the whipped topping over the cake.
Top with remaining candy corn and chopped peanuts.