Slow-Cooker Portobello Garlic Butter Beef Brisket Step-by-step instructions

Before you start

Before you start, make sure your slow cooker is clean and ready. Trim the brisket of excess fat, leaving a thin layer for moisture. Slice the portobello mushrooms thickly—about 1/4-inch thick—so they hold up during the long cooking time.

Mince the garlic or use pre-minced garlic for convenience. If you're using store-bought compound butter, let it soften slightly so it's easier to slice into medallions. Have all your ingredients measured and ready to go, then simply layer them in the slow cooker as directed.

Instructions

Layer the Ingredients

1. 1Layer the Brisket
   Place the trimmed beef brisket flat in the bottom of a 6- to 7-quart slow cooker. If needed, cut the brisket to fit, but keep it in large pieces.
   Look for The brisket sits in a single layer, touching the bottom of the insert.
   Tip Trim excess fat but leave a thin layer for moisture.
2. 2Add Mushrooms and Garlic
   Scatter the thickly sliced portobello mushrooms over the brisket, then sprinkle with the minced garlic. Spread them evenly so they cover the meat.
   Look for Mushrooms and garlic form a rough layer over the brisket.
   Tip Thick slices hold up during long cooking.
3. 3Top with Butter Medallions
   Place the garlic-herb compound butter medallions on top of the mushrooms and garlic. Distribute them evenly so they melt over the meat as it cooks.
   Look for Butter medallions sit on top, ready to melt.
   Tip If the butter is very cold, slice it thinly for even melting.

At the end of this phase, you'll have a neat layer of brisket on the bottom, topped with portobello mushrooms and minced garlic, and finished with pats of garlic-herb butter. The ingredients should be evenly distributed, with the butter on top so it melts down over everything as it cooks. The raw meat should be visible around the edges, and the mushrooms should look fresh and plump. This is the moment to make sure everything is arranged well before the slow cooking begins.

Slow-Cook to Tender

4. 4Cook Low and Slow
   Cover the slow cooker and cook on LOW for 8 to 10 hours, or on HIGH for 5 to 6 hours, until the brisket is fork-tender and easily shreds. Let it rest for 3 minutes before slicing.
   Look for The meat is tender and pulls apart with a fork.
   Safe temperature 145°F (63°C) internal temperature (steaks, chops and roasts)
   Tip Low and slow gives the best texture.
5. 5Rest the Brisket
   Turn off the slow cooker and let the brisket rest in the juices for at least 10 minutes. This allows the meat to reabsorb moisture and makes shredding easier.
   Look for The brisket rests in the savory gravy.
   Safe temperature 145°F (63°C) internal temperature (steaks, chops and roasts)
   Tip Resting keeps the meat moist.

After 8-10 hours on LOW, the slow cooker will be filled with a rich, bubbling gravy. The brisket will be fork-tender, and the mushrooms will have softened and absorbed the buttery sauce. The aroma will be intensely savory with garlic and herbs.

The meat should easily pull apart with a fork, and the gravy will be a deep, glossy brown. The internal temperature should be at least 145°F (63°C), but for the best texture, it will be higher. This is the sign that the brisket is ready to rest.

Shred and Serve

6. 6Shred and Serve
   Use two forks to shred the brisket directly in the slow cooker, mixing it with the mushrooms and buttery gravy. Serve over warm buttered egg noodles or as desired. Let it rest for 3 minutes before slicing.
   Look for Shredded beef is coated in rich gravy.
   Safe temperature 145°F (63°C) internal temperature (steaks, chops and roasts)
   Tip For extra flavor, spoon extra gravy over each serving.

After resting, the brisket will be even more tender and juicy. When you shred it with forks, it will separate into long, moist strands, coated in the buttery mushroom gravy. The mushrooms will be soft and flavorful, and the gravy will be rich and aromatic. The dish is now ready to serve over warm buttered egg noodles or your favorite side. The final texture should be melt-in-your-mouth tender, with every bite full of savory garlic-butter goodness.

Common mistakes

One common mistake is cooking the brisket on high for too short a time, which can result in tough meat. Always aim for low and slow—8 to 10 hours on LOW is ideal. Another mistake is skipping the rest time after cooking; letting the meat rest in the juices helps it reabsorb moisture and makes shredding easier.

Also, don't over-trim the fat; a little fat is essential for flavor and moisture. Finally, be generous with the garlic and butter—they create the delicious gravy that makes this dish so good.

How to tell it’s done

The brisket is done when it's fork-tender and easily shreds with a fork. The internal temperature should read at least 145°F (63°C) for whole cuts of beef, but for the most tender results, you'll want it to reach around 195°F (91°C) to break down the collagen.

The meat should pull apart with little resistance, and the mushrooms should be soft and coated in the buttery gravy. If the meat isn't shredding easily, continue cooking for another 30-60 minutes until it reaches the desired tenderness.

• Steaks, chops and roasts: 145°F (63°C) in the thickest part, then a 3-minute rest