In a large bowl, season short ribs generously with salt and pepper. Add the browning sauce. Use your hand and massage each short rib to ensure each piece is coated. Set aside.
Heat a Dutch oven, or a heavy bottom pot over medium-high heat. Add 2 tbsp. of grapeseed oil In batches, brown short ribs on each side, adding little more grapeseed oil before each batch. Move short ribs to a plate and a set aside.
Add onion, celery and carrots. Sauté until vegetables are soft and fragrant. Mix in tomato paste. Add wine to deglaze pot, then add beef broth. Add short ribs, rosemary, thyme, oregano, bay leaf and garlic cloves. Bring to a simmer. Cover and reduce heat to low. Let short ribs braise for 3 hours.
Turn off heat. Remove as many aromatics as possible. Using a strainer, strain the liquid from the pot into a measure cup to get about 3 cups.
In a large skillet, heat butter over medium heat. Whisk in flour, and whisk until creamy and there are no visible lumps. Stir in reserved liquid. Keep stirring until liquid and flour mixture is blended. Add short ribs to skillet and simmer for 5-7 minutes. Spoon the sauce over the short ribs.
Serve warm with side of choice.