Cut the crusts off the bread. Spread mayo and Dijon mustard on one side of each slice.

Build your sandwich by layering bread → Swiss → ham → turkey → bread → turkey → ham → Swiss → bread.

In a shallow bowl, whisk together the egg, milk, salt, and pepper until smooth.

Heat a skillet over medium heat and melt a generous amount of butter.

Dip both sides of the sandwich into the egg mixture, letting it soak lightly like French toast.

Cook the sandwich for 3–4 minutes per side until deeply golden brown and the cheese is fully melted. Press gently while cooking to seal the layers together.

Remove the sandwich from the pan, dust with powdered sugar, slice in half, and serve warm with raspberry jam for dipping.