Prepare the filling by mixing chocolate chips, mini marshmallows, and graham cracker crumbs in a bowl.
Lay two slices of bread on a clean surface and evenly distribute the filling over each slice.
Top with the other two slices of bread to create sandwiches and press down gently.
In a shallow bowl, whisk together the egg and milk until fully combined.
Dip each sandwich in the egg mixture, coating both sides evenly.
Heat vegetable oil in a pan over medium heat until shimmering.
Carefully place the sandwiches in the hot oil, frying each side for about 2-3 minutes or until golden brown.
Once done, remove the sandwiches from the pan and place them on paper towels to absorb excess oil.
Cut the fried s’mores sandwiches in half and serve warm with dipping sauces if desired.
