To begin, sauté the butter and onion together until the onions are tender and golden.
While the onion is sautéing, deseed and finely mince the chipotle peppers. Set them aside for now. (I recommend wearing gloves when handling the peppers, especially if you wear contacts like I do.)
In a mixing bowl, combine the torn bread and milk.
Add the ground beef, but pull it apart into little bits. This makes mixing the ingredients easier and prevents overworking the meat mixture. Over working leads to tough, dry meatloaves or meatballs, when making those.
Add the Worcestershire sauce, salt, pepper, thyme, minced chipotle peppers, beaten egg, and the sautéed onions.
Gently toss the ingredients until they are just combined.
Press the meat mixture into a loaf pan.
Bake at 350°(F) until the meat thermometer reads 160.° (About 45-50 minutes)
Top with the shredded cheese and let it melt for the last 10 minutes or so of baking.
Let the meatloaf rest for 15 minutes before slicing.