Line your muffin tin with paper liners and set it aside. And preheat your oven to 350° F. In a small bowl, sift together flour, baking powder, cinnamon and salt and set aside.
In a medium bowl, cream together sugar and oil. Add eggs and sour cream and milk then mix well.
Slowly add dry ingredients into wet ingredients. Mix until your carrot muffin batter is formed.
Fold your shredded carrots into the carrot muffin batter. Scoop batter into your prepared lined muffin tin, filling each section about ¾ of the way.
Bake for 22-25 minutes or until a toothpick comes out clean from the center of a muffin. Allow to cool completely on a wire rack
For the Cream Cheese Frosting
Use an electric mixer to beat together cream cheese, butter, sugar and milk. Mix until ingredients are well-combined and form semi-stiff peaks. Use an offset spatula to frost each cooled muffin.