Season the roast with salt and pepper. Add some oil to a Dutch oven and sear the roast on all sides. Transfer roast to crockpot.
Add onions and garlic. Pour the beef broth over the roast. Tie the sprigs of herbs together with butcher twine and drop them into the crockpot. Add the bay leaf. Cook on low for 6 to 8 hours until roast falls apart. Add the mushrooms and peas the last 2 hours.
Taste and adjust seasonings. Remove the sprigs of herbs and bay leaf. Serve.