Slow Cooker Mushroom and Onion Italian Beef

This beef is slow cooked with Italian herbs, mushrooms, and onions. It's perfect as a nice sub sandwich and as a main dish.
Course Main Course
Cuisine American
Keyword Beef Dip, crockpot, Rump Roast, slow cooker, Sub
Prep Time 5 minutes
Cook Time 8 hours
Total Time 8 hours 5 minutes
Author Lyuba Brooke


  • 2.75 - 3 lbs rump roast
  • 1 large yellow onions
  • 8 oz baby portobello mushrooms
  • 1 lb garlic bulb
  • 1 tsp crushed red pepper flakes more or less depending on your spicy tolerance
  • 1/2 Tbsp dry oregano
  • 1/2 Tbsp dry thyme
  • 1 Tbsp dry parsley
  • 1 Tbsp dry basil
  • 1/2 Tbsp white granulated sugar
  • Salt
  • Beef stock enough to just over the beef about 4-5 cups


  1. Heat up stock and stir in dry herbs, salt, red pepper flakes, and sugar.
  2. Place rump roast into the slow cooker and poke some holes all over the roast using a small knife, about 1 1/2 inches deep. Peel garlic cloves and stick individual garlic cloves into the holes.
  3. Slice onion and mushrooms, not to thin, and add them into the slow cooker.
  4. Pour prepared stock mixture all over the beef and veggies.
  5. Close the lid and cook on low for 8-10 hours.
  6. Take the beef out once it's done and shred it using two forks.
  7. Take onions and mushrooms out of the liquid using a slotted spoon and mix them in with shredded beef.
  8. Save juices from cooking beef for dipping.

Recipe Notes

Recipe from Lyuba, at, All images and content are copyright protected. Please do not use my images without prior permission. If you want to share this recipe, please simply link back to this post for the recipe. Thank you.