Rinse the roast, and then dry it with a paper towel. After drying, marinate the roast with salt, pepper, garlic powder, and lemon juice.
Then coat the roast with a flour layer.
Heat the oil in a large pan at a low flame.
When the oil is hot enough, put in the roast pieces and deep fry, each side for a few minutes. After frying, transfer it to your crockpot bowl.
Fry the diced onions and garlic for a few minutes in the pan and add to the crockpot. Also, add the skillet juices.
Pour a mushroom can into the crockpot.
Cover the crockpot with the lid and let it cook for a few hours.
When it's done, take a cutting board and shred your meat. Cover it with foil so that it stays warmer.
Make a slurry by mixing water and corn starch in a bowl. Pour the mixture into the crockpot juice and whisk it.
Cook it for 10 more minutes to make the gravy thick.
Return the meat to the pot for the purpose to toss it with the thickened gravy.