Whisk together brown sugar and oil. Add the eggs and whisk again until you have a frothy mixture.
Mix the dry ingredients together in a bowl and sift them into the egg mixture while stirring with a rubber spatula. It is important not to whisk the flour mixture in, as this will make the muffins tough in texture.
Add the grated carrot, chopped nuts, and optionally, raisins. Pour the batter into muffin molds and bake for 15-20 minutes at 185 degrees Celsius (365 degrees Fahrenheit).
Check if they are done by inserting a wooden skewer into the center of a muffin. If no batter sticks to it, the muffins are done.
Cream Cheese Frosting:
Beat the frosting ingredients together well with an electric mixer. Spread on the cooled muffins.
Keep the display on
Notes
The muffins, without frosting, can be stored in a plastic bag for a couple of days. They can also be frozen, also without frosting.