I'd suggest you serve the short ribs (great on mashed potatoes) with some of the sauce poured over. If you prefer, you can remove the short ribs to keep warm and thicken the sauce first, either by blending the vegetables into the sauce or by removing some to a pan and adding a slurry of 1tsp corn starch plus 1tsp water and stirring over a medium-low heat until it thickens.