Place a 7 quart saute pan over medium- high heat and drizzle with oil. Working in batches, brown short ribs on all sides until browned and seared, about 6-8 minutes. Transfer to bowl. Pour off all but 3 Tbsp of liquid from pan. Add onions, carrots, and celery to pot and saute until translucent and onions are browned. Add flour & tomato paste and constantly stir until deep red, about 4 minutes. Add wine and stir to combine. Add short ribs, garlic, and fresh herb bouquet and allow to come to a boil, then lower heat to medium, simmering until wine reduces by half. While the wine reduces, prepare a slow cooker set to medium setting. Once wine is reduced by half, carefully remove short ribs, and transfer to prepared crockpot. Once all short ribs have been removed, add beef broth to the liquid. Mix to incorporate, then carefully transfer to slow cooker. Once completed, turn slow cooker to high, cover, and allow to cook for three hours, or until meat is pulling away from bone and slightly shredding.