I've been making this recipe for more than 20 years. It's a family favorite!

3-5 pound chuck roast, trimmed of extra fat
Mustard, your choice (I like Dijon)
Potatoes, carrots and onions
Onion soup mix (or just a bit of beef bouillon granules)

Prepare vegetables and place in the bottom of slowcooker. Rinse roast and pat dry with paper towel. Smear your favorite mustard all over the roast. Sprinkle a package of onion mix over top. No extra liquid is needed. Cook on high about 1 hour, then turn to low for 6-8 hours,  until tender.