Heat oil using the sauté function on your cooker or in a large pot on the stove. Add lamb, season with salt and pepper, brown off to seal, remove and set aside.
Heat butter, sauté veggies until golden, add red wine and cook until reduced slightly, then add tomato paste and stir through. Add chopped rosemary and bay leaf, season with salt and pepper. Add beef bone broth and heat through.
Add back lamb including any meat juices and mix through. Pressure cook 30 mins, slow cook 6-8 hours or simmer on the stove top for 1- 1 ½ hours.
If doing stove top, check and stir occasionally to make sure the bottom isn’t burning and watch the sauce as it reduces down and thickens. It’s ready when the sauce is reduced and meat is tender.
For Instant Pot/multicooker or slow cooker, if you want to thicken up your sauce remove 2-3 cups of liquid to whisk the xanthan in and then add in xanthan gum a tiny sprinkle at a time while whisking constantly to make a 'slurry'. Pour back into your cooker while mixing through to thicken the Low Carb Lamb Stew.
Notes
Net Carbs - 5.2gNote: You can actually add the xanthan gum before cooking to the liquid sauce before adding back the lamb. It may look too thick but then thins out while it’s cooking to a good consistency. Unfortunately we do end up with a few slightly darkened ‘bits’ in the stew and on some of the pieces of lamb because of the sauce being so thick at the start, but we couldn’t taste it and it can be easier than putting the xanthan at the end after cooking. Experiment and decide what you like best!