I'm a pistachio fiend, the sort of person who can work through a pound of in-the-shell nuts in the blink of an eye, and who always knows exactly what flavor of ice cream she's ordering. (Hint: it's green.) So when I showed up at Philadelphia's Pizzeria Stella and saw a pistachio pie on chef Shane Solomon's menu, the deal was done. Gooey fontina cheese, a hint of heat from sweet-spicy purple onions, a drizzle of grassy olive oil, and a beyond-generous blanket of crumbled salty pistachios — it changed how I think of pizza, and it just might be my new favorite slice. — Helen Rosner