In a large, heavy-bottomed pot over medium-high heat, add a tablespoon of oil and sear the short ribs, browning them on all sides for about 8-10 minutes. Remove the ribs and set them aside.

In the same pot, add diced onion, carrots, celery, and minced garlic. Sauté over medium heat for 5-7 minutes until softened.

Pour in the red wine, stirring to deglaze the pot. Allow wine to reduce slightly for about 3-5 minutes.

Return the seared short ribs to the pot. Pour in beef broth until ribs are just covered. Add bay leaves and thyme, then simmer for 2-3 hours.

For slow cooker, place ribs and broth mixture on low for 6-8 hours. Ensure ribs are tender and falling off the bone.

While ribs are braising, peel and chop the potatoes into evenly-sized pieces. Boil in salted water for 15-20 minutes until fork-tender.

Drain potatoes, return to pot, and add butter and heavy cream. Mash until smooth and creamy.

Serve ribs over creamy mashed potatoes, spooning braising liquid over the top.