In the bowl of the crockpot, arrange the onions. Then, place the short ribs on top of the onions. Season with salt and pepper. Add the shallots, garlic, and carrots. Pour over 2 cups red wine, the broth, and cognac (if using). Add the tomato paste, thyme, and bay leaves. Cover and cook on low for 6-8 hours or on high for 4-6 hours.

Crank the heat on the crockpot to HIGH. Discard the bones. Drain any excess grease away from the sauce. Toss the ribs into the sauce. Cook, uncovered for 30 minutes, to help thicken the sauce. Note, the sauce will not thicken much.

Meanwhile, melt 2 tablespoons butter in a large skillet. Add the mushrooms. Cook undisturbed for 5 minutes or until golden. Add 2 tablespoons butter, the sage, and a pinch each of salt and pepper. Cook for 5 minutes, until the mushrooms have caramelized and the butter has browned.

Serve the ribs in the sauce. Spoon the mushrooms over the ribs. Enjoy with potatoes, rice, and/or crusty bread.

Preheat the oven to 325° F. In a large, oven-safe brasier, arrange the onions. Then, place the short ribs on top of the onions. Season with salt and pepper. Add the shallots, garlic, and carrots. Pour over the red wine, the broth, and cognac (if using). Add the tomato paste, thyme, and bay leaves. Cover and roast for 2 ½ to 3 hours or until the short ribs are tender and falling off the bone.

Discard the bones. Drain any excess grease away from the sauce.

Melt 2 tablespoons butter in a large skillet. Add the mushrooms. Cook undisturbed for 5 minutes or until golden. Add 2 tablespoons butter, the sage, and a pinch each of salt and pepper. Cook for 5 minutes, until the mushrooms have caramelized and the butter has browned.

Serve the ribs in the sauce. Spoon the mushrooms over the ribs. Enjoy with potatoes, rice, and/or crusty bread.