This is a variation of a recipe I learned about from Cook's Country from America's Test Kitchen, a PBS cooking program. The episode is "Comfort Food Classics" if you want to watch the program.
3.5 oz. of shitake mushrooms
10 oz. of button mushrooms
1 white onion, diced
4 cloves of garlic, minced
2 and a half cups of beef broth
1 lb. of ground pork
1 lb. of ground sirloin
1/4 cup of rice flour
Smidge of thyme
Healthy smidge of fresh parsley, chopped
Salt and pepper to taste
First, take the saltines and use a food processor to get them to crumbs. Set them aside in a large bowl.
Second, take the shitake mushrooms and 4-6 button mushrooms, place them in the food processor, and pulse until all crumbly. Set this aside in another bowl.
In a large cast iron skillet, sauté the onions until starting to brown and then add in the mushroom mush. Add some salt and pepper. Cook that for 3-5 minutes and then add in the garlic. Cook for a minute or two after adding the garlic. Transfer this to a bowl, so it can cool for a while.
Add the mushroom-onion-garlic mush to the saltines and mix well with two beaten eggs, 1/4 cup of beef broth, and some dashes of Worchestershire sauce. Add in the ground pork and sirloin and mix well.
Instead of using a loaf pan, use the skillet. Dump the meaty goop into the pan and shape it into a loaf. Place the skillet into a 375 degree oven for approximately an hour or until the internal temp of the meat is 170 degrees.
Remove the meatloaf from the skillet and place on a cutting board. Place aluminum foil over the meat, so it stays warm.
Scrape out the meat leakage that remains in the skillet and place the remaining button mushrooms (sliced) into the skillet. Add some salt, pepper, and thyme. Cook on medium for roughly five minutes and then add in the rice flour. Cook for a minute. Pour in the beef broth and a bit of Worchestershire. Heat until it boils and then reduce to low. In five minutes, the gravy should be ready.