Meatloaf - Pork and Beef

This is a really good, very traditional meatloaf recipe from Food 52. I will make it again, as I think it is my favorite meatloaf recipe thus far (I like mushrooms and carrots in there, and all the parsley). I modified it just a little to be GF. This hit the spot for something easy and filling, and cozy for this cloudy bit of weather. I ate it with fried potatoes. Yum.

Meatloaf
olive oil 
2 stalks celery
1 medium carrot
¹/₂ small onion 
¹/₂ cup parsley with large stems removed
1 small bell pepper diced
6 mushrooms, with tough part of stems removed
1 pound 80% ground beef
1 pound ground pork
1 cup GF oats
2 large eggs, lightly beaten
spoonful of tomato paste (or a small diced tomato)
2 tsp salt, plus pepper to taste
2 tablespoons heavy cream (optional)
splash of fish sauce (opt, for some umami!)
ketchup to slather on top of loaf

1. Preheat oven to 375° F and lightly oil a rectangular baking dish or loaf pan. Dice celery, carrot, parsley and onion into small bits. Alternatively, process in a food processor until the vegetables are ground.
2. Dice the pepper and mushrooms and sauté them in a small amount of olive oil until the pepper softens.
3. To a large mixing bowl add the meat, ground vegetables, sautéed pepper and mushrooms, oats, egg, tomato paste, salt and pepper, and cream (if using). Mix with your hands until it's all combined. (To check the seasoning, fry off a tiny test patty, taste, and adjust accordingly.)
4. Plop the meat into the oiled baking pan and shape into a loaf. Cover with ketchup. 
5. Bake for 1 hour, remove from oven, and let sit for 15 minutes before slicing.