Beginning this morning, through day's end Saturday, diners with a sweet tooth won't need to visit a fancy restaurant to score desserts from one of the city's top pastry chefs, Alex Feick. Instead, they can just visit her new pop-up at Pie Oh My(2719 Sutton Boulevard, Maplewood).Feick is a Maplewood resident who previously served in the kitchens of Niche (from 2014 to early 2015) and the Libertine (until October).…