Because of their elongated, oval-to-rectangular shape and shallow depth, they are specifically designed as individual gratin dishes or creme brulee dishes (though they can also double as small pie or tart molds). The fluted, wavy rim helps create a decorative edge for baked crusts or potato gratins. They are likely made of durable vitreous porcelain or ironstone to handle oven-to-table heat. Common mid-century manufacturers of this exact style include companies like Pillivuyt (France) or Pyrex/Corning (Centura/Centura-style ceramics), but you can easily verify by checking the underside for a maker's stamp
