Preheat your oven to 275°F (135°C).

Generously season both sides of the chuck roast with salt and pepper.

Melt 1 tablespoon of unsalted butter in a skillet over medium-high heat and sear the roast until browned on all sides, about 3 minutes per side.

Carefully transfer the seared roast to a Dutch oven or slow cooker. Surround it with the sliced onions and baby carrots.

Sprinkle the ranch dressing mix and au jus gravy mix evenly over the roast.

Add the minced garlic on top, followed by the remaining tablespoon of butter.

Cover and bake in the oven for approximately 4 hours, or until the meat is fork-tender.