Test-batch, or prototype Pyrex, is also rare, like "Barcode" stripe casserole dishes in blue and yellow, or the "Pink Stems" small oval casserole dish, the only shape made in the sought-after pattern.

In an oval gratin dish or 7-by-11-inch Pyrex dish, arrange citrus in a spiral, alternating Cara Cara and blood oranges. Preheat broiler. Meanwhile, make the sabayon: Set a metal bowl over a pot to ...