The Virtues of Glazing

• Glazing the tart serves several useful purposes. First, it serves as a gentle adhesive to hold the fruit together and keep it in its intended arrangement. Second, it provides a seal against the outside air. Without it, the cream filling in the tart can lose moisture and crack, and perishable fruit or berries -- especially if they're sliced -- deteriorate. Finally, the glaze's shiny, glossy surface adds greatly to the dessert's visual appeal. There are many ways to glaze the tart, depending what you have in your pantry.

Commercial Glazes

• Most supermarkets have one or more brands of commercial fruit glaze, either in the baking aisle or displayed prominently in the produce section. Most are designed to be added to cold water or clear juice, thickening it to a clear and slightly glossy gel that can be brushed onto the fruit. Commercial glaze usually contains industrial thickening agents such as carageenan, guar gum or locust bean gum, which have no flavor or color. Some must be cooked and include starches, gelatin or gelatin-like thickeners such as agar agar. These must be used while warm, because they'll set firmly once cooled.

Gelatin

• Pastry chefs often use a clear and glossy glaze called "miroir," the French word for "mirror." To make miroir, you'll need a small amount of simple sugar syrup, made by boiling a cup each of water and sugar until the sugar's completely dissolved. For every cup of mirror glaze you need, sprinkle a tablespoon of unflavored gelatin over a half-cup of cold water and wait for it to dissolve. Warm it in the microwave and stir until the gelatin's completely dissolved, then stir in the sugar syrup. Use the glaze as soon as it starts to thicken. Miroir can be tinted with food coloring.

Jams and Jellies

• Jams and jellies are another glaze that's widely used by professional bakers and pastry chefs, especially in Europe. Apricot jam is used for light-colored fruits, while red currant jam or jelly is more common with red or dark-colored fruits and berries. Whichever jam you choose, heat it gently in a double-boiler and thin it with a small amount of water or liqueur. Strain out any pieces of fruit, and brush the thinned jam over your fruit. Less-conventional choices, such as apple jelly or marmalade, work well with some fruit combinations.

Cornstarch Glaze

• If you want maximum versatility with a minimum of advance planning, you can also make a serviceable glaze with cornstarch. You'll need to whisk a small amount of cornstarch into cold water to make a slurry, then whisk the starch mixture into a pot of heated sugar syrup or clear fruit juice. The starch will thicken the mixture gently, as it does for gravies and sauces. Let the mixture cool to room temperature, then brush it over your fruit. It won't last as long or be as shiny as some of the other glazes, but it's quick, simple, effective and requires no special ingredients.