Preheat oven to 250 degrees
Salt and pepper your roast on all sides. Heat 1 tbsp of fat or oil in a large Dutch oven, add the roast, and sear over medium heat until it has a nice brown crust all the way around ( about 5-7 minutes each side). Remove the roast and let the pan cool slightly.
In the same pan, melt 3 tbsp butter and add the onions. Salt and pepper to taste. Sauté onions over medium heat until tender and starting to caramelize (about 15-20 minutes). Add the garlic and cook 3 additional minutes. Put the roast back into the pan.
Add all other ingredients, stir to combine and bring to a simmer. Cover and transfer to preheated oven for 4-6 hours or until meat pulls apart easily with a fork.
Note: If using a slow cooker, follow the same directions. When you're ready to add everything into the oven, instead, add everything to your slow cooker and cook on low for about 8-10 hours.
To serve: I like this best served the first day just like a French onion soup, in a bowl with a slice of toasted bread and melted Gruyere cheese on top. However, it's also great on top of mashed potatoes, pierogies, or egg noodles. My absolute favorite thing about this dish is making French dip sandwiches in the days to follow with the leftovers. Serve the meat on a nice hoagie roll with a horseradish mayo and melted cheese and dip in the delicious French onion broth.