1 Heat Butter In A 4 To 6 Quart Pot On Medium Heat. Add The Chopped Leeks, Toss To Coat With The Butter. When The Leeks Are Heated Enough So They Begin To Sizzle In The Pan, Lower The Heat To Low And Cover The Pan. Cook Until Soft, But Don'T Let The Leeks Brown. 2 Add The Parsnips And Olive Oil, And Toss To Coat. Sprinkle On The Salt. Add The Stock And Water. Add The Strips Of Lemon Zest. Bring To A Boil And Reduce To A Low Simmer. Cover And Cook Until The Parsnips Are Completely Tender, At Least 30 Minutes. 3 Remove And Discard The Lemon Zest. Add The Parsley. Pur