Brown the mushrooms with parsley, garlic and as much salt as you wish.
In a non-stick pan cook and whisk the egg; when it is completely cooked, add as much salt and pepper as you wish.
Cut the bagel in two, heat the two parts in the oven and create the sandwich with the scrambled egg, the mushrooms, tomato cubes and cooked ham slices.
Finally, close this original alternative to the classic egg-and-ham recipes by adding the second half of the bagel.