Chef Thomas Keller together with Lena Kwak, the French Laundry's culinary researcher, developed a gluten-free flour. Cup4Cup is made from cornstarch, white rice flour, brown rice flour, milk powder, tapioca flour, potato starch, xanthan gum. It can replace all-purpose flour cup for cup, hence the product's name.
Florence Fabricant from the New York Times experiment with Cup4Cup and wrote "It works very well, though the cake textures were more delicate than usual and I found that the pie crust was best rolled somewhat thicker for ease of handling, since the lack of gluten made it less malleable than pastry with regular flour."
Cup4Cup can be purchased at Williams-Sonoma stores and online for $19.95 and will soon be available at Bouchon Bakeries.