01 -
Start by warming up your oven to 450°F. Toss the bread and crackers into a food processor and pulse until they become coarse crumbs. Add the melted butter, then pulse a little more to mix. Spread the crumbs on a rimmed baking sheet, then bake them for about 3-5 minutes. Stir every so often until the crumbs turn golden. Scoop the crumbs into a shallow dish (a pie plate works well) or leave them on the pan and pile them up. Lower the oven heat to 400°F after that.
02 -
Lay down each slice of ham and sprinkle 1/4 cup of cheese on top. If the ham is small, overlap two slices to make a bigger piece. Roll the cheese snugly inside, forming a tight little roll, and set them aside.
03 -
Dry off the chicken with paper towels. Cut a pocket into the thickest part of each breast. Tuck two of those ham and cheese rolls into each pocket. Gently press the chicken flap over the filling and seal by pressing down (toothpicks can help keep it closed if needed). Sprinkle both sides with some salt and pepper. Let the filled chicken chill in the fridge, covered, for at least 20 minutes.
04 -
Beat the eggs along with the mustard in one shallow dish. Pour flour into another dish. Take the chicken from the fridge. Coat each piece first in flour, then dip it into the egg mixture until covered, and finally press it into the toasted crumbs, making sure the crumbs stick well on all sides.
05 -
Grease a rimmed baking sheet lightly, then put the chicken on it. Check that your oven rack is in the middle before baking. Bake the chicken until it’s a lovely golden color and cooked through—around 25-30 minutes. (Make sure the meat, not the filling, reaches 160°F on a thermometer.)
06 -
After baking, leave the chicken alone for 5 minutes to cool slightly before serving.