Preheat the oven to 350°F (180°C) and grease a 13x9-inch cake pan. Set aside.
In a large mixing bowl, combine sugar, vegetable oil, and eggs with a spatula. Add grated carrots, orange zest, and juice from the orange. Mix until combined.
1 cup light brown sugar, 1 cup vegetable oil, 4 large eggs, 2 cups finely grated carrots, 1 large orange
In a medium bowl, combine flour, baking powder, baking soda, cinnamon, nutmeg, and salt. Sift the dry mixture into the large bowl with the wet ingredients. Mix until just combined.
2 cups all-purpose flour, 2 teaspoons baking powder, 1 teaspoon baking soda, 1 teaspoon ground cinnamon, ¼ teaspoon grated nutmeg, ½ teaspoon salt
Pour carrot cake batter into prepared baking dish and bake for 20-25 minutes or until a toothpick inserted in the center comes out clean.
Allow the cake to cool down completely before frosting it.
To make the frosting, beat together butter and confectioners' sugar in the bowl of a stand mixer fitted with the paddle attachment until light and fluffy.
¼ cup unsalted butter, 1 cup powdered sugar
Add vanilla extract and cream cheese and beat until blended. Frost cooled cake.
1 teaspoon vanilla extract, 8 oz cream cheese