This amazing Monte Cristo sandwich is a classic combination of ham and Gruyère cheese on thick-sliced white bread, dipped in an egg and milk batter and pan-fried in butter until golden. I dust it with powdered sugar and serve it with red currant or raspberry jam, all ready on the table in less than 30 minutes.
In a shallow large bowl or a pie tin, whisk together the eggs and milk to make an egg batter. Place in the refrigerator until ready to use.
Place 4 slices of sandwich bread down on a cookie sheet tray lined with parchment paper, or a large serving dish or platter.
Evenly spread on the mayonnaise and Dijon mustard onto the slices of bread.
Next, evenly layer on the cheese and ham and then place on the top slice of bread.
Add the butter to a very large frying pan over low to medium heat and then dip a sandwich one at a time on all sides in the egg batter.
Place the sandwiches into the pan and cook for 3-4 minutes per side or until golden brown all around. Also, stand the sandwiches up and brown on the slice sides.
Remove sandwiches, garnish with powdered sugar and serve alongside jam or jelly.
Notes
For this sandwich to be successful every time, I highly recommend holding the pan at low-to-medium heat and waiting for the butter to bubble at the edges before the first sandwich goes in. This one is a grilled cheese and a French toast at the same time, so the outside has to brown at the same rate the cheese melts inside, and rushing the heat gives me a blackened crust over cold gruyere. I give each side a full 3 to 4 minutes, and if the cheese is behind, I drop a lid on the pan for the last minute instead of chasing more color.Shred the gruyere off the block, not pre-shredded. Why? Well, pre-shredded cheese is dusted with anti-caking starch that keeps it from melting into the smooth pouring texture this sandwich needs. Shredded off a block on a box grater takes 30 extra seconds so nothing crazy and a must-do in my opinion.Press the bread firmly into the batter, both sides and all four edges: The bread has to actually soak up the batter, not just get glazed with it, or the outside cooks up like a lightly wet piece of toast instead of French toast.Cover the pan with a lid on the last minute if the cheese is behind: If the outside is super golden brown but the cheese has not fully melted, a lid on the pan for the last 60 seconds traps steam and finishes the inside without pushing the outside past brown.Finish stubborn cheese in the oven if the pan will not get there: For a sandwich with a lot of gruyere or a thick cut of ham, pull it out of the pan once both sides are golden brown, then finish on a parchment-lined sheet tray in a 325°F oven for 5 to 7 minutes.Cheese on both sides of the ham, not just one: A single layer of cheese under or over the ham leaves the sandwich lopsided, with a dry stripe of ham through the middle instead of a full melt. Cheese on both sides of the ham is what gives every layer that gooey cheesy pull I love.Make-Ahead: I fry the sandwiches up to an hour before serving and hold them on a parchment-lined sheet tray in a 200°F oven so the outside stays crispy and the cheese stays melted. This sandwich is meant to be eaten right out of the pan, but the oven-hold is a solid backup if the whole batch is going down at once.How to Store: I cover any leftover sandwiches and keep them in the fridge for up to 4 days. Wrapped tight, the sandwich also freezes for up to 3 months, and I thaw it in the fridge overnight before reheating.How to Reheat: I set the sandwich in a hot pan over low-to-medium heat with a fresh pat of butter and cook a couple of minutes per side until the outside is crispy again and the cheese is pouring. A 350°F oven on a parchment-lined sheet tray for 8 to 10 minutes also works well. Skip the microwave. It undoes every bit of the crispy exterior.How to Freeze: I wrap the fully cooked and cooled sandwich in plastic wrap and foil and freeze for up to 3 months. Thaw overnight in the fridge before reheating in a pan or oven.