Heat a skillet over high heat until hot. Add the oil and wait a minute until it shimmers. Place the short ribs into the skillet and sear until nicely browned on all sides. You won't want to crowd the pan, brown the ribs in batches if necessary.
Combine the barbecue sauce, beef broth, pumpkin, and mustard in a small bowl. If the barbecue sauce has been chilled, warm it in the microwave for a few seconds before adding to the sauce.
Place the onion and garlic in the bottom of the slow cooker, top with the sauce mixture and combine. Nestle the browned short ribs into the slow cooker and turn to coat with the sauce. Cover and cook on LOW for 6-8 hours, or on HIGH for 3-4 hours, or until the meat is tender.
In the last 30 minutes of cooking, add the beans, cubed squash, and curly kale.
Notes
Beans: Use your favorite combination of chili beans like black beans, red kidney beans, or pinto beans.
Storage: Refrigerate leftovers in an airtight container for 3–4 days.
Freezer: Freeze cooled chili in freezer-safe containers for up to 3 months.
Reheating: Warm gently on the stovetop or in the microwave until heated through.
Make Ahead: This chili tastes even better the next day after flavors have melded.