British columnist and cookbook writer Beattie (The Table of Content: A Vegetarian Dinner Party Book for All Seasons) has come up with over 100 meatless Mexican soups, main courses, salads, snacks and desserts to be prepared quickly. Savory offerings include chili-spiked chickpea soup, Sopa de Garbanzos; tomato-tortilla layered Mexican Lasagne; and eggplant and roasted pepper Fajitas. Desserts are highlighted by super-fast coconut ice cream (Helado de Coco), prepared with canned coconut milk, corn syrup, half-and-half and flavored with rum. The use of canned corn or canned creamed corn--called for in Corn Soup, the corn-based stew, Pepi n, and Mexican Corn Pudding--may strike American cooks as somewhat odd, but when speed's the issue, such products can be a blessing. Occasionally other British usages (e.g., "Blacken the tomato skins") might give pause to inexperienced American cooks, but many of Beattie's selections will please adventurous palates--and beat the clock. (July) FYI: This book and a simultaneous publication, 30-Minute Vegetarian Indian Cookbook by Mridula Baljekar ($21.95 176p ISBN 0-88001-600-0), launch Ecco's new ethnic 30-Minute Vegetarian Cookbook series.