Frozen-custard lovers need grieve no more. Yes, Kohr Bros. Frozen Custard indeed vacated its spot in Riverfront. But the Double Rainbow Dessert Cafe(300 SW First Ave., Suite 131, Fort Lauderdale, 954-527-5219), brought to us by the same folks who operate Tout Sweet Ice Cream Parlor & Bakery Cafe in Delray Beach, has come to the rescue. In addition to supplying San Francisco's Double Rainbow premium ice creams, the cafe will continue to produce homemade frozen custard the likes of which you get at Coney Island. Of even more interest, the cafe already offers home-baked pastries and is developing a full line of eats, including salads, sandwiches, and hot dogs. It's even open for breakfast bagels. And while a schmeer of cream cheese obviously won't give you the same brain-freeze rush as the custard, it will deliver those much-needed calories.