1. 1. Preheat your oven to 325°F.

2. 2. Heat the olive oil in a large oven-safe pot or Dutch oven over medium-high heat. Season the short ribs with salt and pepper, then sear them on all sides until they are beautifully browned. Remove the seared ribs and set them aside.

3. 3. In the same pot, add the chopped onion, garlic, carrots, and celery. Cook these aromatics until they are softened, about 5-7 minutes.

4. 4. Stir in the tomato paste, followed by the crushed tomatoes, beef broth, thyme, rosemary, and bay leaf. Return the seared short ribs to the pot and bring the mixture to a simmer.

5. 5. Cover the pot and transfer it to the preheated oven. Let the Short Rib Ragu braise for 2.5-3 hours, or until the meat is incredibly tender and falling off the bone.

6. 6. While the Short Rib Ragu is braising, prepare the Parmesan Mashed Potatoes by boiling the peeled and chopped russet potatoes in salted water until tender, about 15-20 minutes.

7. 7. Drain the cooked potatoes and return them to the pot. Mash the potatoes with the unsalted butter and milk, then stir in the grated Parmesan cheese. Season with salt and pepper to taste.

8. 8. Carefully remove the short ribs from the sauce and shred the tender meat, discarding any bones. Return the shredded meat to the flavorful sauce, stirring to combine. Adjust seasoning with additional salt and pepper as needed.

9. 9. To serve, scoop a generous portion of the creamy Parmesan Mashed Potatoes onto a plate or shallow bowl. Top with the Short Rib Ragu and garnish with fresh parsley if desired.