Preheat the grill to medium heat (350F).
Cut crusts off of the bread and roll bread flat with a rolling pin. Trim to form a rough 4 inch circle.
Butter each side of the bread and place in the muffin tin to form a cup, pressing the bread against the sides of the tin. Patch any holes with another small piece of buttered bread.
Combine eggs, garlic powder, onion, seasoning salt, and pepper and beat with a whisk until frothy.
Pour into muffin tin filling the bread cup approximately ¾ full. Add a few cubes of ham to each muffin and top with cheese.
Place muffin tin over the grill, close the lid and cook for 5-6 minutes.
Rotate the muffin tin around on the grill and cook for an additional 5-6 minutes or until the egg centers are set.
