Preheat the oven to 375.
Add olive oil to a skillet over medium heat. As soon as it is shimmering, add the onions. Saute for 3-5 minutes until softened. Add the carrots and mushrooms. Add a splash of water at any point if the veggies are sticking. Saute until the mushrooms are softened. Add in the garlic and dried Italian herbs.
Transfer half of this mixture to a large bowl. Add the tomatoes to the skillet with the remaining half of vegetables. Bring up to a simmer.
Add the oatmeal, grated parmesan and salt to the vegetables in the bowl. Using your hands (because it is more fun), fold in the ground beef and sausage (or whatever combo of meat you choose). Add a splash of red wine.
Cut the mixture into 4-ounce balls, about the size of a hamburger yet balled up. Any size will do and smaller balls will bake up faster.
Cook the 4-ounce balls for 15 minutes on a baking sheet. Flip over and continue heating until the outside is golden, about 10-15 more minutes. Press into the ball with your finger and when it feels firm it is done.
Smaller balls will take 12-18 minutes to cook through, depending on their size.
Add red wine to the marinara sauce and coat each ball with the sauce. Simmer for a few minutes or transfer to a baking dish and heat up at later time.