Tarts provide bakers of all skill levels with the opportunity to put their best food forward. Baked in ornamental pans with fluted edges and -- usually -- lift-out bottoms, these single-crust sweet or savory pies lend themselves to visually appealing fillings. If you feel the need for a tart but don't have a tart pan handy, or don't have the correct size and shape, you can usually improvise.
Pies and tarts are the closest of kin, and a suitably sized pie plate is a good substitute for a tart pan. They usually -- though not always -- lack the decorative fluted rim of a tart pan, and seldom have a lift-out bottom for easy removal of the finished tart. Both of those shortcomings can be easily overcome. The tart's crust can be given an attractively scalloped edge by pinching the dough between your fingers, compensating for the plain-edged pan. To make the tart easy to remove, cut a square of parchment paper to fit the bottom of the pan, leaving four longer strips to act as handles for sliding the cooled tart from the pan.
A Quiche Pan
A quiche pan is extremely similar to a tart pan, down to the deeply fluted edge and -- usually -- lift-out bottom. The primary difference is that quiche pans tend to be slightly smaller in diameter, and deeper by about 1/2 inch. In many cases those changes in dimensions will cancel out, and you'll be able to use your recipe unaltered and simply lengthen the baking time to compensate for the deeper filling.
You don't necessarily need a full pan, just some sort of form to hold your dough in place on a parchment-lined baking sheet. The ring from a springform pan is an excellent choice, both sturdy and readily available. Line the ring with a collar of parchment, and lay your cut pastry dough carefully into the ring. For tarts in other sizes and shapes, make a free-form collar of folded aluminum foil -- stiffened with cardboard, if you wish -- and place that on the sheet. This type of form can also be used to make square or oblong tarts on a rectangular sheet pan.
If your goal was mini tartlets, rather than a full-sized tart, you have different options. Muffin pans in jumbo, standard and mini sizes represent three obvious choices, providing an easy way to produce tartlets in quantity. Heatproof glass custard cups and small ceramic ramekins are other options. In each case, you can make it easier to remove the finished tartlets by leaving a long strip of parchment beneath the dough as a handle. Tartlets can also be made in open forms, using small foil collars. Use sections cut from a cardboard shipping tube or smaller gift wrap or paper towel tube to stiffen them.