It is the filling, rather than the type of pastry dough, that makes a pie or tart distinctive, and it is here that imagination counts. Apples may appear sliced, chopped or puréed; most berries look best in an open tart with a shiny glaze. Fruits that tend to discolor, such as pears and peaches, are poached before being arranged in a baked pastry shell and glazed with the poaching syrup. Often a layer of pastry cream is hidden beneath the fruit. Other fruit pies may be baked with a double crust, the trick being to brown the top evenly while thoroughly cooking the base. A preheated baking sheet helps here, and the fruit may be mixed with cornstarch, in American style, to absorb the juice. Deep-dish pies with a top crust are a British specialty, baked in an oval dish with a support in the center to hold up the crust.