Imagine the best French toast you've ever had combined with the best ham and cheese sandwich you've ever had, topped with perfectly poached eggs, and you have Chef John's Monte Cristo Benedict recipe. You don't need any Hollandaise because the poached egg yolks are the sauce.
Using day-old French bread is crucial; fresh bread will absorb the custard too quickly and become overly soggy. When pan-frying, maintain a consistent medium heat to achieve a beautiful golden crust without burning. The poached eggs are the star here, acting as the 'sauce,' so ensure they are perfectly cooked with runny yolks. A splash of white vinegar in the poaching water helps the egg whites set more cleanly. For an extra layer of flavor, consider using a good quality, sharp aged Cheddar to contrast with the mild Havarti. A final sprinkle of flaky sea salt will elevate the seasoning.