chocolate zucchini sheetcake

Ingredients

• - 1 1/2 cups packed light brown sugar
• - 1/2 cup sugar
• - 1/2 cup butter, softened
• - 1/2 cup vegetable oil
• - 3 large eggs
• - 1 tsp. vanilla extract
• - 1/2 cup buttermilk
• - 2 1/2 cups flour
• - 1/2 tsp. ground allspice
• - 1/2 tsp. ground cinnamon
• - 1/2 tsp. salt
• - 2 tsp. baking soda
• - 5 tbsp. unsweetened coco powder
• - 4 cups firmly packed grated unpeeled zucchini
• - 1 cup semisweet chocolate chips
• - powdered sugar