Season and Sear the Beef: Begin by seasoning the beef stew meat with salt and pepper. Heat the vegetable oil in a skillet or frying pan over medium-high heat. Once hot, add the seasoned beef and sear for about 5 minutes, or until it's browned on all sides. This step helps enhance the flavor of the stew. After searing, transfer the beef to your slow cooker.
Layer the Vegetables: In the slow cooker, add the cubed potatoes, chopped onion, minced garlic, and sliced carrots on top of the seared beef.
Season with Herbs: Sprinkle the dried oregano, thyme, and rosemary over the vegetables and beef in the slow cooker.
Mix in Tomato Paste and Broth:Add tomato paste and beef broth until well combined.
Cook on Low: Cover the slow cooker with the lid and set it to cook on low heat for 5-7 hours. This long cooking time allows the flavors to meld, and the meat and vegetables to become tender.
Add Frozen Peas: About 1 hour before the stew is finished cooking, add the frozen peas to the slow cooker. Stir gently to incorporate them into the stew.
Thicken the Stew: In a separate bowl, whisk the flour into some of the juice from the stew until it forms a smooth paste. Slowly pour this paste back into the slow cooker while stirring to thicken the stew. This should take about 15 minutes.
Adjust Seasonings: Taste the beef stew and adjust the salt and pepper if needed. You can also add more herbs at this point for extra flavor.
Serve: Once the beef is tender, and the peas are heated through, your hearty slow cooker beef stew is ready to serve. Ladle it into serving bowls and enjoy!