Bring water, garlic, and rosemary to a boil in a large pot.

Add lima beans and cook for 18 minutes, or until very soft.

Drain, reserving 1 cup of the cooking liquid.

Using an immersion blender, process very well, making sure the garlic is completely blended and absorbed into the mixture.

Add the reserved cooking liquid a small amount at a time, until the consistency reaches that of a whipped potato. You may not need to use all of the liquid. I like to start with ½ a cup of the liquid, and add it in ¼ cup increments, usually totaling no more than 1 cup.