Pat dry, and then season chuck roast with salt and pepper
Heat oven to 325 Degrees F or prepare a slow cooker
In a Dutch oven or skillet, heat oil over medium-high heat until sizzling hot. Sear until nicely browned (about 4 minutes/side)
Chop the onions and the celery
While the roast is searing, measure the liquid of your choice and stir in the chopped garlic
Blend the Spicy Beer Mustard and Horseradish
Remove the roast from the Dutch oven and scatter the onion and celery mixture into the pan in which you browned the meat or into the slsow cooker
Spread the Spicy Beer Mustard and Horseradish mixture over both the top and the bottom of the chuck roast.
Place the onion and celery mixture into the Dutch oven, or if using, the slow-cooker. Arrange the chuck roast on top of the vegetables and pour the liquid into the roasting pan.
Cover with a tight fitting lid, and pop into preheated 325 degree oven. Roast for 2 1/2 hours or until easily piereced with a fork
Do the same as above when cooking the roast in a slow cooker. Turn heat to either low or high. If low heat, cook the roast 10-12 hours, and if high heat, 5-6 hours.
Add potatoes and carrots into the broth surrounding the roast, and continue roasting until vegetables are tender, about 1 more hour. Baste vegetables several times during roasting.
When roast is fork tender and vegetables cooked, lift roast to a platter and with a slotted spoon, remove vegetables and place around roast. Serve the remaining broth in a bowl for guests to ladle over the meat and vegetables if desired.