Lay one sheet of filo dough down on a 8 or 9-inch tart pan, brush it with a thin layer of melted butter. Repeat with the remaining sheets of filo dough, rotating the sheets slightly with each layer so you get full coverage of the tart pan, and brushing a thin layer of butter on each sheet of dough. Heat the strawberry jam in the microwave or on a stovetop until it becomes liquid; brush the strawberry jam on the very top layer of filo dough.

Meanwhile, toss the strawberry slices in a small bowl with the sugar. Arrange the strawberries on the top layer of filo dough in a circular pattern. Pour any remaining strawberry-sugar liquid on top.

Trim all loose ends of the filo dough to about 1 inch from the edge of the pan. Gently tuck in the filo dough so that it forms a neat crust around the strawberries.

Bake at 350 for 25 minutes or until the filo dough is golden brown and the strawberries are bubbling.