Preheat the oven to 350 degrees F (175 degrees C). Spray a 2-quart casserole dish with nonstick spray.
Combine beets, carrots, walnuts, onions, oats, and bread crumbs in a large bowl.
Beat eggs, parsley, bagel seasoning, and liquid aminos in a smaller bowl. Mix into the veggie mixture and stir to combine. Transfer to the prepared casserole dish and top with ketchup.
Bake, uncovered, in the preheated oven for 1 to 1 ½ hours, depending on how moist or dry you want it.
