Lay out bread, side by side. On first four pieces, spread 1 tablespoon of bleu cheese dressing on each slice. Top this with approximately 1 ounce of blue cheese crumbles and 2 ounces of roast beef.
On each of the remaining 4 slices, spread 1 tablespoon of cherry preserves and top with ¼ cup of cherries. Bring both sides of sandwich to meet each other.
In bowl, whisk together eggs, milk and salt. Pour out into very shallow pan or plate. Set sandwiches in the mixture, flipping to both sides, until most of the egg bath has been soaked up.
Heat skillet to medium heat and add ½ tablespoon of the butter. When butter starts foaming, set a single sandwich in the mixture and cook on each side, until egg-soaked bread firming up and outside browning, approximately 6 to 8 minutes total. Continue process with remaining butter and prepped sandwiches.