If I base my view of Mexican sweets on what street carts and restaurants serve, I’d wrongly think that the best this country has to offer are sugar-topped churros, eggy flans and the ubiquitous fried ice cream. Thanks to pastry chef Fany Gerson’s “My Sweet Mexico” (Ten Speed Press, 2010), I know that our neighbors to the south enjoy an array of delectable confections. With recipes for and histories of pastries, breads, desserts and drinks Gerson guides me through the colorful world of Mexican sweets. Although “My Sweet Mexico” landed in bookstores – and on my bookshelf – a few weeks ago, I’ve already found several new, favorite recipes. Convent cookies are among them. Laced with ground, caramelized almonds, these cookies are lovely with afternoon coffee or tea. Likewise, I adore “polvorones.” Commonly known as Mexican wedding cookies, these delicate, powdered sugar-coated treats are perfect for any occasion. I’m similarly smitten with “aceite de vainilla” or vanilla cordial. An uncomplicated yet ambrosial beverage, vanilla cordial consists of dried vanilla beans, simple syrup and vodka or …