Season beef with salt and pepper, heat oil in a large skillet over medium heat. Cook short ribs in skillet browning on all sides, transfer to crock pot. Wipe out the pan and return to heat
Cook bacon until crisp, remove to a paper towel lined plate
Remove all but 1 tbsp of dripping in the pan, reduce heat to medium and add in the onion. Cook and stir until softened and translucent. Add in flour, mustard, tomato paste, 1 tsp salt and ½ tsp pepper, cook and stir for 1 minute.
Remove skillet from heat and pour in Guinness. stir to scrape browned bits from the bottom of the pan. Pour over short ribs in the crock pot. add in bacon, bay leaf, and beef broth to crock pot, cover and cook on low for 8 hours
Serve on their own or over hot mashed potatoes or cooked egg noodles.