Set the oven to 350° F.

Pour the milk in a bowl and soak the bread in the milk.

In a saucepan, empty the Au Jus and Brown Gravy mixes. Add a small amount of water and whisk until there are no clumps. Add the remainder of the water according the directions on the package.

Tie the thyme, parsley, bay leaves, and sage together using cooking twine or in  cheese cloth. Place the herbs in the gravy.

Bring the gravy to a boil then reduce it simmer. Allow to simmer for 15 minutes.

Mix all the ground beef, onion, egg, garlic powder, salt and pepper together, including the soaked bread and milk. Form the meat mixture into oblong meatballs.

Heat 1 Tablespoon of olive oil in a medium skillet. Sear on all sides as you would a regular meatball.  Once cooked, place them in a roasting pan that you can cover.

Cook the Katletis in batches. After removing each batch, use a small amount of water and a wooden spoon (or similar item) to loosen up the bits left behind. Reserve the liquid to use later. 

Strain out the large pieces from the reserved liquid from step 8. Add the liquid to the gravy and whisk together. Remove the herb bundle and discard. Pour the gravy mixture over the Katletis in the roasting pan.

Cover and bake for 30 minutes.