On the weekend, Kim Son’s carts carry an average of 70 dim sum items. Don’t miss the velvety eggplant stuffed with shrimp paste, mushroom-capped meatballs, Chinese broccoli, golden-fried turnip cakes, slurpy rice noodle rolls, cylinders of shrimp paste wrapped in seaweed and deep-fried in tempura batter, pork dumplings with quail…