These should be cooked in their skins; but before putting them into the oven, brush off all grittiness. Place in a moderate oven, cooking gradually until nearly done, then quicken the oven and brown. Serve with plenty of fresh butter.
--from Godey's Lady's Book Receipts and Household Hints by Sarah Annie Frost, Evans, Stoddart & Co, 1870, p. 173. (For more great 19th century recipes, check out the rest of this book on Google Books.)
(I have made this before and it is yummy! I cooked them in a 350F oven until they were fork-tender. Then, I turned the broiler on to brown them. Watch it very carefully so you don't burn your tasty onions! I also seasoned them with salt and pepper to taste.)