Crockpot Portobello Butter Bottom Round Roast Step-by-step instructions

Before you start

Before starting, pat the roast dry with paper towels and let it sit at room temperature for up to 30 minutes. Slice the portobello mushrooms about 1/2-inch thick, and mince the garlic.

Measure the butter and have it ready. No other prep is needed—no browning, no seasoning, no extra steps. The slow cooker insert should be clean and dry.

Instructions

Layer the Ingredients

1. 1Layer the Roast
   Place the beef bottom round roast in the center of a 6-quart slow cooker. There is no need to sear or season—just set it in the insert.
   Look for The roast sits in the center of the insert, leaving room around it for the mushrooms.
   Tip If the roast is larger than the insert, trim it to fit, but keep the pieces thick.
2. 2Add Mushrooms and Garlic
   Scatter the thickly sliced portobello mushrooms over and around the roast. Sprinkle the minced garlic evenly over the top.
   Look for Mushrooms and garlic cover the surface of the roast in an even layer.
   Tip Thick slices hold their shape during the long cook and become meaty.
3. 3Top with Butter
   Place the whole stick of salted butter on top of the roast and mushrooms. It will melt and baste the meat as it cooks.
   Look for The butter sits prominently on top, ready to melt down over everything.
   Tip Salted butter seasons the jus; if using unsalted, add a pinch of salt.

At the end of this phase, the slow cooker holds the raw roast, with mushrooms and garlic scattered over it and a whole stick of butter on top.

The ingredients are arranged in a single, even layer. The butter is solid but will begin to melt as the cooker heats. Nothing is seasoned or browned—just ready to go.

Slow-Cook to Tender

4. 4Cover and Cook Low
   Cover the slow cooker and cook on LOW for 8 to 10 hours, until the roast is fork-tender and easily pulls apart. Do not open the lid during cooking. Let it rest for 3 minutes before slicing.
   Look for A rich, buttery aroma fills the kitchen; the roast is tender enough to shred.
   Safe temperature 145°F (63°C) internal temperature (steaks, chops and roasts)
   Tip Low and slow is key—high heat can toughen a lean cut like bottom round.
5. 5Check Temperature and Rest
   After 8 hours, check that the internal temperature of the roast reaches at least 145°F (63°C). Remove the roast to a cutting board and let it rest for at least 3 minutes before slicing or shredding.
   Look for A thermometer inserted in the thickest part reads 145°F (63°C) or higher.
   Safe temperature 145°F (63°C) internal temperature (steaks, chops and roasts)
   Tip Resting lets the juices redistribute, keeping the meat moist.

After 8 to 10 hours on low, the kitchen smells richly beefy and buttery. The roast is deeply browned in places and falls apart when prodded with a fork. The mushrooms are soft and darkened, and the jus is bubbling gently around the edges. The internal temperature reads 145°F (63°C) or higher.

Slice and Serve

6. 6Slice or Shred the Beef
   Slice the roast against the grain into thick pieces, or shred it with two forks. The meat should be very tender and pull apart easily.
   Look for The beef separates cleanly with a fork, showing moist, tender fibers.
   Tip For shredding, hold the roast steady with a fork and pull with the second fork.
7. 7Spoon the Jus Over
   Stir the braising liquid in the slow cooker to combine the melted butter, mushroom juices, and garlic. Spoon the jus over the sliced or shredded beef before serving.
   Look for A golden, glossy jus coats the back of a spoon.
   Tip Taste the jus and add a pinch of salt if needed—the butter already seasons it.

The roast is sliced or shredded, and the golden jus is spooned over the top. The meat is moist and tender, with visible grains. The mushrooms are meaty and coated in butter. The jus pools on the plate, ready to soak into mashed potatoes or bread.

Common mistakes

A common mistake is opening the slow cooker too often, which lets heat escape and extends cooking time. Another is using high heat, which can make a lean roast dry and tough.

Also, resist the urge to add liquid—the beef and mushrooms release plenty of moisture. Finally, don't skip the rest; it allows the juices to redistribute.

How to tell it’s done

The roast is done when it is fork-tender and the internal temperature registers at least 145°F (63°C) for whole-cut beef. Insert an instant-read thermometer into the thickest part of the roast, avoiding any bones.

If the meat shreds easily with a fork, it is ready. Let it rest for at least 3 minutes before slicing or shredding to keep it juicy.

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