This slow cooker 3-ingredient root beer corned beef is exactly how my dad makes it every single year for St. Patrick’s Day—and now I pull it out anytime I want a no-fuss, fall-apart roast. It sounds almost too easy: corned beef, root beer, and a little Dijon. But after an all-day simmer, the brisket turns tender and pink inside, with a dark, syrupy root beer glaze that clings to every slice. It’s perfect for busy days when you want that cozy, all-day-cooked flavor without hovering over the stove.
Serve the corned beef straight from the slow cooker, sliced or shredded, with some of that dark root beer glaze spooned over the top. It’s great alongside buttery boiled potatoes, roasted carrots and cabbage, or simple mashed potatoes. I also love piling leftovers onto toasted rye or slider buns with Swiss cheese and a swipe of extra Dijon or horseradish sauce. A crisp green salad or steamed green beans helps balance the richness, and if you’re into it, an ice-cold root beer or light beer ties the whole meal together.
Slow Cooker 3-Ingredient Root Beer Corned Beef
Servings: 6

Ingredients
3 to 3 1/2 pound corned beef brisket with seasoning packet, rinsed and patted dry
1 (12-ounce) bottle or can root beer (not diet)
2 tablespoons Dijon mustard
Directions
Place the corned beef brisket in the bottom of a slow cooker, fat side up. Discard the seasoning packet or save it for another use—my dad skips it for this recipe so the root beer flavor really shines.
In a small bowl, whisk together the root beer and Dijon mustard until the mustard is mostly dissolved. It doesn’t have to be perfect; you just want it mixed enough to spread the flavor around.
Pour the root beer–mustard mixture evenly over the corned beef, making sure some liquid runs underneath the meat. The brisket doesn’t need to be fully submerged; it will release juices as it cooks.
Cover the slow cooker with the lid and cook on LOW for 8 to 10 hours, or until the corned beef is very tender and easily pulls apart with a fork. For a more sliceable texture, start checking around 7 hours; for fall-apart, shreddy meat, lean toward the full 10.
Once the corned beef is tender, carefully transfer it to a cutting board, letting any juices drip back into the slow cooker. Tent loosely with foil and let it rest for about 10 minutes so it’s easier to slice or shred.
While the meat rests, skim off any excess fat from the surface of the cooking liquid. If you’d like a thicker, glazier sauce like in the photo, ladle some of the liquid into a small saucepan and simmer it on the stove over medium heat for 10 to 15 minutes, until slightly reduced and syrupy.
Slice the corned beef against the grain into 1/4-inch slices, or shred it with two forks if you prefer. Return the meat to the slow cooker or place it in a serving dish and spoon the dark, reduced root beer glaze over the top. Serve warm with extra sauce on the side.
Variations & Tips
For a sweeter finish, stir 1 to 2 tablespoons of brown sugar into the root beer and Dijon mixture before pouring it over the brisket. If you miss the traditional spice packet flavor, you can tuck it into a small piece of cheesecloth or a tea infuser and drop it into the slow cooker, then remove it before serving so the glaze stays smooth. To lean more savory, swap half of the root beer for low-sodium beef broth while keeping the total liquid amount the same. You can also broil the cooked, sliced corned beef on a foil-lined sheet pan for 3 to 5 minutes, brushing with some of the reduced glaze, to caramelize the edges. Leftovers make incredible sandwiches: pile warmed corned beef on toasted bread with Swiss cheese, more Dijon, and a quick coleslaw or sauerkraut. For meal prep, cook the brisket on a Sunday, then portion it into containers with potatoes and veggies for easy reheat-and-eat lunches all week.