Liquid

Water is usually the liquid of choice in classic French tart doughs because it does not impart any residual flavor. However, due to its lack of fat, water does contribute to gluten development. Milk, eggs, juice, sour cream, or even cream cheese may also be used, each affecting the finished dough in a different way. Milk will add some flavor and heighten the color of the baked dough. Juices, especially acidic ones, will break down gluten, but will also prevent the desired browning during baking. Cream, sour cream, and cream cheese all contain fats, acids, and sugars, which prohibit gluten development. A bit of acid also produces a very flaky finished product.