At this tiny Cantonese bakery, there’re buns and more buns, corn sausage to pineapple taro to—yes—hot dogs and cheese, plus mini tarts, sponge cakes, and porky pastries. Not all flavors are amazing, but Mei Sum has some delights, including the Chinese analog to Snowballs and Twinkies: coconut-shrouded mochi balls and cream-filled sweet flower cake.