Gennifer Choldenko’s Chasing Secrets takes place in the late 1800s — this recipe is one that might have been served at a luncheon. From the Boston Cooking School Cookbook:
Few grains salt
1 teaspoon lemon juice
2 1⁄2 tablespoons orange juice
1⁄2 tablespoon butter (for pan)
2 tablespoons powdered sugar
Separate yolks from whites. Beat yolks until thick and lemon colored; add salt, lemon juice and orange juice. Beat whites until stiff and dry, cutting and folding them into the first mixture until they have taken up mixture.
Heat pan, and butter sides and bottom. Turn in mixture, spread evenly, place on range where it will cook slowly. When well “puffed” and delicately browned underneath, place pan on center grate of 350°F oven to finish cooking. Omelet is cooked when firm to the touch when pressed by the finger.
Remove skin from oranges and cut in slices, lengthwise. Fold in one-third of the slices of orange, well sprinkled with powdered sugar; put remaining slices around omelet, and sprinkle with sugar.