Cut the short ribs between the bones into two-inch cubes. Place in a bowl. Season with salt and pepper. Add the flour and toss to coat each piece; shake off the excess.
Heat the olive oil and butter in a frying pan. Brown the meat well. Scoop out and drain.
At this point, you have the option of frying the potato and carrot wedges in the flavorful oil. It's optional but frying them before they are added to the stew gives them better texture. You don't need to cook them all the way through. Just fry at a high temperature until the edges are lightly browned. Then, set the aside until it's time for them to go into the slow cooker.
Heat another frying pan. Dump the bacon and chorizo and cook until browned and a generous amount of fat has been rendered. Scoop out the browned bacon and chorizo.
Reheat the rendered fat and saute the onion, garlic, bell pepper, thyme and oregano.
Line the slow cooker with the sauteed aromatics and the fat in which they were cooked. Place the browned beef short ribs on top followed by the bacon and chorizo. Pour in the diced tomatoes. Add a teaspoonful of salt and about a quarter teaspoon of pepper. Throw in the bay leaf.
Turn on the slow cooker. I like to start at HIGH for two hours then switch to LOW for another four hours or so.
After the Mediterranean beef stew has been cooking for four hours, taste the sauce. Add more salt and pepper, as needed.
If you did not fry them, add the potato and carrot wedges and olives to the meat, and stir lightly. If you had fried the potato and carrot wedges, add them during the last hour of cooking.
When the stew is done, taste the sauce one last time and adjust the seasonings again, if needed.
Sprinkle the stew with parsley before serving hot with rice or crusty bread.