Beat the eggs together with cream, half-and-half, or milk. Beat in cinnamon and salt. Melt the butter in a large frying pan. Dip the challah slices, one at a time, into the egg mixture, making sure that each slice is well coated. The challah should absorb a little of the egg mixture but not enough to get soggy. Fry each battered challah slice for 2-3 minutes on each side until they are golden brown. Don't fry too fast or the inside will be wet and gooey. Serve with your favorite jam, maple syrup, honey, cinnamon, sugar, or plain. Note: Heavy cream really is the best liquid to use in this recipe.