Preheat the oven to 350 degrees. Line 9×13 baking dish with parchment and spray with oil

In a mixing bowl, beat together the ingredients for the cake until well combined.

Pour the batter into baking dish

Bake for 30-35 minutes until browned and cooked through.

Let the cake cool for 15 minutes.

Mix together the ingredients for the icing until smooth and creamy.

Spread the icing over the warm cake and let cool before serving.