In a large bowl, mix together the flour, salt, pepper and chili powder. Toss the oxtails to coat. Heat a large oven-proof pot with lid over high heat. Add the olive oil and sear the oxtails on all sides. Remove to a plate to rest. Add the onions, carrots and celery and saute for 5-8 minutes or until onions are tender. Pour in the beer and add chiles. Stir to combine. Add the oxtails back to the pot and top with fresh thyme. Add the lid and place in the preheated oven. Braise for 1 hour and turn the oxtails. Continue braising for 2 more hours. Remove from the oven and allow to cool for 5 minutes. Use 2 forks to shred the meat from the tail bone. Set aside.

In a medium bowl add the shaved broccoli, carrots and cabbage and toss with the mayo, Sriracha and salt and pepper.

Add about 1/4 cup of oxtail to the bottom baguette and top with 1/4 cup slaw, top with the baguette top and secure with a toothpick. Repeat with remaining 7. Serve immediately.