Preheat your oven to 350°F (175°C) and line a cupcake pan with paper liners.

In a large bowl, whisk together the all-purpose flour, granulated sugar, brown sugar, baking powder, baking soda, ground cinnamon, and salt.

In another bowl, combine the vegetable oil, eggs, and grated carrots. Mix well.

Pour the wet ingredients into the dry ingredients and mix until just combined. Fold in the walnuts and raisins if using.

Scoop the batter into the prepared cupcake liners, filling each about 2/3 full.

Bake in the preheated oven for 18-20 minutes, or until a toothpick inserted into the center comes out clean.

Remove from the oven and allow to cool in the pan for 5 minutes before transferring to a wire rack to cool completely.

In a medium bowl, beat the softened cream cheese and butter together until smooth and creamy.

Gradually add the powdered sugar and vanilla extract, mixing until well combined and fluffy.

Once the cupcakes are completely cool, use a piping bag or a spatula to frost the cupcakes with the cream cheese frosting.

Optionally, sprinkle some additional chopped walnuts on top for garnish.