this area, but so was the concept of the gourmet burger movement, giving birth to chains like In-N-Out Burger, with many variations of burgers including chili, multiple patties, avocado, special sauces, and Angus or wagyu beef. Common accompaniments include thick milkshakes in various flavors like mint, chocolate, peanut butter, vanilla, strawberry, and mango. Smoothies are a common breakfast item made with fresh fruit juice, yogurt, and crushed ice. Agua fresca, a drink originated by Mexican immigrants, is a common hot-weather beverage sold in many supermarkets and at mom and pop stands, available in citrus, watermelon, and strawberry flavors; the California version usually served chilled without grain in it. The weather in Southern California is such that the temperature rarely drops below in winter, thus, sun-loving crops like pistachios, kiwifruit, avocadoes, strawberries, and tomatoes are staple crops of the region, the last often dried in the sun and a feature of salads and sandwiches. Olive oil is a staple cooking oil of the region and has been since the days of Junípero Serra; today the mission olive is a common tree growing in a Southern Californian's back garden. As a crop olives are increasingly a signature of the region along with Valencia oranges and Meyer lemons. Soybeans, bok choy, Japanese persimmon, thai basil, Napa cabbage, nori, mandarin oranges, water chestnuts, and mung beans are other crops brought to the region from East Asia and are common additions to salads as the emphasis on fresh produce in both Southern and Northern California is strong. Other vegetables and herbs have a distinct Mediterranean flavor which would include oregano, basil, summer squash, eggplant, and broccoli, with all of the above extensively available at farmers' markets all around Southern California. Naturally, salads native to Southern California tend to be hearty affairs, like Cobb salad and Chinese chicken salad, and dressings like green goddess and ranch are a staple. California-style pizza tends to have disparate ingredients with an emphasis on vegetables, with any combination of chili oil, prawns, eggs, chicken, shiitake mushrooms, olives, bell pepper, goat cheese, and feta cheese. Peanut noodles tend to include a sweet dressing with lo mein noodles and chopped peanuts. Fresh fish and shellfish in Southern California tends to be expensive in restaurants, but every year since the end of WWII, the Pismo clam festival has taken place where the local population takes a large species of clam and bakes, stuffs,