Preheat the oven to 325°.
Salt the short ribs on all sides.
Add the flour and five spice to a bowl, stir to combine.
Dredge the short ribs in the flour mixture, coating on all sides.
Heat the olive oil in a pan over medium high heat.
Sear the short ribs on all sides, remove from pan.
Add the onions, cooking over medium heat until starting to caramelize, about 15 minutes. Add the beer, scraping to deglaze the bottom of the pan.
Stir in the broth and tomato paste. Add the short ribs back in, cover, and add to the oven.
Cook for about 3 hours or until fork tender, checking on the ribs about every hour, turning over and returning to the oven until done.