Bake the croissants as directions on package states, you can bake them up earlier in the day or even the night before.
Once the croissants have cooled, preheat oven to 350F and spray a 9x13 casserole dish with some non stick spray.
Cut open the 8 croissants, spread the mayonnaise evenly between all 8, then cut the deli ham and swiss cheese and divide evenly over the 8 croissants.
Cut each sandwich into 4 pieces then spread pieces out in the casserole dish covering all areas.
In a large measuring cup or bowl whisk together the eggs and milk then add a dash of salt & pepper. Pour egg mixture over the croissants being sure to cover all areas.
Cover with tinfoil and bake in the oven for 30 minutes, then remove foil and bake another 10 min.
Remove from oven and let cool for 5 minutes then cut into 6 equal servings, each one weighing approx 6oz.
*Note, I kept the recipe more traditional for a monte cristo sandwich but feel free to add in some veggies if you wish.
*This recipe will freeze well and leftovers should be kept in the fridge