Turn your Slow Cooker on *LOW*.

Add your Olive Oil to a pan & sear your beef stew meat on medium/high heat for approx 5-7 minutes.  You may have to do this in 2 steps - depending on your size of pan & the amount of stew meat you have on hand.  Once seared, add your stew meat to your slow cooker.

Cook & brown your onions in the same pan for approx 5-6 minutes.  Allowing them to cook in the juice of the stew meat - only makes them better.  Once they're finished, add to your slow cooker.

Add your can of tomatoes, sweet potatoes, spinach and corn to your slow cooker.

In a small mixing bowl, add all your ingredients for your marinade/stew sauce.  You can add anything that your personally like, but the ones that are listed above are our family's favorite.  Mix together & add to your slow cooker.

***I typically wait until I add water to see how much liquid will be in the slow cooker after a few hours of cooking.***  But if you are going to leave, or go to work, I would add about 1/2 cup of water to your stew before you leave.

Once it has cooked for at least 4-5 hours, (and I am at home) I'll boil water (or use your Keriug to disperse hot water) and mix 1/2 cup of boiling water along with some of the juice liquid from the slow cooker in a separate bowl..   Add your flour to the hot liquid.  Mix the flour mixture really well, to get rid of the flour lumps.  Doing this while your liquid is hot, will really help your flour mix to dissolve.  Once it has mixed thoroughly, add it to your slow cooker, and mix it in with your stew.

Turn your slow cooker on warm for about 1 hour, and serve when you're ready.