In a small sauce pan heat the lima beans, chicken broth, rosemary, salt and pepper to boiling. Reduce heat and let simmer for a few minutes until limas are heated through, approx 5 minutes. Remove from heat and drain the lima beans reserving approximately 1/2 cup of liquid.
Place hot lima beans back into the sauce pan. Add butter and chicken broth in 1 Tablespoon increments as needed. Either with a masher or with an emersion blender (I use the emersion blender) puree the lima bean/butter/broth mixture until silky smooth and they resemble "green mashed potatoes". If they seem too dry, add some more of the reserved chicken broth until the consistency is to your liking.
These are a healthy alternative in our house and everyone loves them. Even the veggie haters always leave raving about these lima's!