The current recipe serves about 2 as a fruit dip or toast spread. It seems to be pretty well proportioned. Multiply if you wish to serve more or to frost a cake.
Also, adjust the amount of soymilk according to your desired consistency.
In small bowl, (I use a 1/2 cup ceramic measuring bowl) blend ingredients until smooth. Use less soymilk for a thicker frosting, more for a runnier dip.
This dip/frosting/spread would probably also work very well with maple syrup added, or with flavors/extracts in place of cinnamon. Example: substitute vanilla extract for cinnamon and you would have the perfect cream cheese carrot cake icing!