In a 2 1/2 or 3 quart sauce pan, add the parsnips, a pinch of salt, one tablespoon of butter and enough broth to cover the parsnips halfway, about 1/2 cup. Bring to a boil over medium-high heat and then reduce heat to a simmer.
Continue to cook, checking frequently to make certain the broth doesn't completely evaporate before the vegetables have fully cooked. Add more broth as needed. Parsnip are ready when they are very soft but still hold their form and most of the broth has evaporate, about 20 minutes.
In the bowl of a food processor, add the cooked parsnips, along with any broth remaining in the pan, and the rest of the butter. Puree until parsnips break down. Add enough cream to obtain a consistency similar to that of mashed potatoes.
Transfer the parsnips back to sauce pan. Add the lemon juice and mix thoroughly. Season to taste with salt and pepper. Serve immediately. Will keep refrigerated for 2-3 days.