1Preheat oven to 375. Allow your ground meat to warm up a bit on the counter before mixing (from thawed, maybe 15-20 min.)
2Oil or grease your baking dish. We used a rectangular 10 x 7, 2.5 qt. shallow baking dish. If you use something with higher sides (like a standard loaf pan), you might need a little longer in the oven.
3Finely grate the carrot and celery and dice the onion. Using a fork, beat the eggs a little. Add the breadcrumbs and oats to a large bowl.
4Add all the other ingredients to the bowl with the breadcrumbs, adding the mixed eggs and tomato paste last. Mix together using your hands for a few minutes, until it starts to become a bit tacky. If it needs a bit more moisture, use a few more tablespoons of tomato sauce.
5Press it into your baking dish, and cover with your savory ketchup (our brand from Wholesome Valley Farm is delicious and not too sweet.)
6Bake for 1 hour (internal temperature of 160), then allow to rest for 10 minutes before slicing. Serve with extra ketchup. Leftovers make delicious sandwiches or meatloaf burgers.
Inspired by Food52's Meatloaf, Plain & Simple.