Place Fennel Into A Saucepan Of Boiling Water, Simmer For 10 Minutes Or Until Tender. Lightly Oil A 2 Quart Baking Dish. Layer In The Fennel Grated Cheese, And Yogurt That Has Been Thinned With Milk To The Consistancy Of Buttermilk. End With A Layer Of Cheese. Season With Salt And Pepper. Bake At 350 Degrees For 20 Minutes Or Until The Top Is Golden Brown. Allow Dish To Cool While You Are Making The Puree. Roast Pepper And Garlic In 350 Degree Oven Until The Skin Of The Pepper Is Turning Dark Brown. Allow To Cool In A Paper Bag And The Remove Skin From Pepper. Add Pepper And Garlic To A Food Processor And Puree Adding Enough Water To Achieve A Barely Pourable Consistancy. Put Puree On The Bottom Of A Plate And Then Set A Square Of The Gratin In The Middle.