In a large nonstick skillet heat the oil until shimmering. Add the beef cubes and season to taste with salt and pepper. Brown the meat on all sides and remove to the crock of a 5 quart slow cooker.
In the drippings left in the pan, sauté the onion, mushrooms, and garlic until the onions are clear and the mushrooms start to brown, about 7 to 10 minutes. Stir in the herbes de Provence and season with salt and pepper. Transfer this mixture to the crock.
Add the tomato sauce, water, and bay leaf to the crock, stirring gently to combine. Cook on LOW heat for 6 to 8 hours or on HIGH for 4 hours. Right before serving, stir in the olives. Serve hot.
Nutritional values are approximate and are based on ⅛ of the recipe. Refrigerate leftovers promptly and use within 4 days.To cook in the instant pot: If you'd like to cook the stew in the electric pressure cooker, follow steps 1 and 2 as directed, except place the meat and vegetables in the cooker insert. Add the seasonings and liquid.Secure the lid and close the pressure valve. Set the machine for 25 minutes manual and then allow a 10 minute natural release before releasing the pressure and taking off the lid. Stir and serve.To freeze: chill the stew completely before storing in freezer-safe containers and store in the freezer for up to 2 months. Thaw in the refrigerator and reheat when ready to serve.