The fine food folks at Better Homes and Gardens have focused their attention on home baking that comes from the heart and the heartland. The Better Homes and Gardens New Baking Book (Meredith, $25.95, ----------) has over 600 recipes packed into a handy, snap-open ring binder, with lots of instructional color photos and the Better Homes' know-how that has made their cookbooks and their magazines so popular for so many years. The recipes run the gamut of goodies that come out of the oven, redolent, rich and ready to add a special dimension to breakfast, dinner, tea time, snack time and party time. There are cakes and cookies, brownies and bars, yeast breads and quick breads, pies and pastries, plus a special section on Baking with the Kids that encourages children to enjoy the process, not just the finished product. With Thanksgiving and Christmas so near, the chapter devoted to Holiday Classics may be exactly what the dessert doctor ordered--imagine the oohs and ahs you'll get when the meal is crowned by a Pear and Mincemeat Tart, with an orange-infused cream cheese center, glowing Rum Babas or a Royal Christmas Cake studded with fruits and nuts and frosted with swirls of snowy-white icing. Whether you're a kid new on the baking block or an old hand at handling dough, you'll find treasures here to share with friends and family.