Preheat oven to 350°F. Grease and flour a 9x5-inch loaf pan or line with parchment paper.
In a medium bowl, whisk together flour, baking powder, baking soda, cinnamon, nutmeg, and salt.
In a large bowl, whisk granulated sugar, brown sugar, oil, eggs, and vanilla until smooth.
Stir in grated carrots, orange zest, and orange juice.
Add dry ingredients to the wet mixture. Stir gently until combined. Do not overmix.
Pour batter into the prepared loaf pan. Smooth the top with a spatula.
Bake for 50–60 minutes, or until a toothpick inserted in the center comes out clean.
Let bread cool in the pan for 10 minutes. Transfer to a wire rack to cool completely.
To make the glaze, beat cream cheese, powdered sugar, orange juice, and vanilla until smooth.
Drizzle glaze over the cooled bread. Let it set for 10 minutes before slicing.