Combine the flour, sage, salt and pepper in a shallow dish or tin. Coat the ribs on all sides with the seasoned flour. Shake off excess.
Heat a large Dutch oven over high heat for 3 minutes. Add the canola oil; wait a minute or 2, until the pan is very hot and almost smoking. Place the short ribs into the pan; sear until they are nicely browned on all 3 meaty sides. You will have to sear the meat in batches. Do not crowd the pot. Be patient; allow 4–5 minutes per side. When the ribs are nicely browned, transfer them to a plate to rest.
Reduce heat to medium; add the onion. Stir with a wooden spoon, scraping up all the browned bits in the pan. Cook 3–4 minutes, until the onion just starts to soften. Add 12 ounces of beer. Stir. Add the pumpkin. Stir in the tomato paste, Dijon mustard, whole-grain mustard, vinegar and molasses. Mix well. Bring sauce to a boil. Return ribs to the pot. Stand them up if necessary to fit them all in. Add the remaining 12 ounces of beer to almost cover the ribs. Add as much of the chopped kale as fits. Cover the pot. Simmer on low for 3 hours. Transfer the ribs to a large platter, remove ties. Spoon lots of braising juices over the ribs.
About this recipe
* Editor’s note: We used Pumpkin Porter from Four Peaks Brewery, available only for a brief time in the fall, as our beer. You can also make your own purée from local pumpkins or squash in place of the canned product.