Grate corn from cobs into a bowl and measure correct amount.
Beat eggs vigorously and stir in onion, salt, and cayenne.
Heat milk until a film forms, skim, and stir into corn mixture.
Pour into 6 buttered custard cups and place in a shallow pan containing about 1 inch of boiling water.
Bake in a preheated 325° oven for 50 to 60 minutes or until a knife inserted in center of custard comes out clean.
Shortly before custards are done, cut tomatoes in slices, dust both sides with flour, sprinkle with salt, and saute in heated butter over a brisk heat.
Fry several minutes on each side.
Remove from skillet, stir in 1 or 2 teaspoons of flour, and pour in cream.
Cook, stirring constantly, until sauce thickens just enough to make a smooth gravy.
Taste and add salt if necessary.
Remove custards from cups, place on a hot platter, surround with tomatoes, and spoon sauce over tomatoes.