Preheat the oven to 350°F (175°C) and line a muffin tin with paper liners.

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

In another bowl, mix the oil, eggs, and vanilla extract until well combined.

Add the wet ingredients to the dry ingredients and stir until just combined. Fold in the grated carrots.

In a small bowl, combine the chopped nuts, brown sugar, flour, melted butter, and cinnamon. Mix until crumbly.

Spoon the muffin batter into the prepared muffin tin, filling each cup about 2/3 full.

Sprinkle the nut crumble topping evenly over each muffin.

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

Allow to cool in the tin for 5 minutes before transferring to a wire rack to cool completely.