
Gluten-free | Dairy-free | Nightshade-free | Paleo | Low-Carb | Whole30
Cut roast in half. Combine the mustard, rosemary, garlic salt, thyme and pepper; rub over roast.
Chop the parsnips into 1-inch pieces and dice the onion.
Spread the carrots and parsnips in the bottom of the slow cooker. Place the chuck roast on top, moving the carrots and parsnips out from under and around the roast, if needed for the lid to close. Scatter the onions around and on top of the roast. Pour the wine around the slow cooker.
Cover and cook on low 6 hours.
After 6 hours, add the mushrooms around and on top of the roast and cook another 2 hours for a total of 8 hours.