Preheat oven to 350°F (175°C).

Line an 8×8-inch baking pan with parchment paper and lightly grease.

2. Mix Dry Ingredients:

In a medium bowl, whisk together flour, baking powder, baking soda, salt, cinnamon, and nutmeg. Set aside.

3. Mix Wet Ingredients:

In a large bowl, combine vegetable oil, granulated sugar, and brown sugar until smooth.

Beat in eggs, one at a time, followed by vanilla extract.

4. Combine Wet and Dry Ingredients:

Gradually stir the dry ingredients into the wet mixture until just combined.

Fold in grated carrots and nuts, if using.

5. Bake: