2 tbsp butter
1 tbsp canola oil
1 large onion, cut into wedges
3 lb rump roast
3 carrots peeled and sliced
3 medium russet potatoes, cut into large cubes
2 bay leaves
1/2 tsp salt
1 box dry onion soup mix (both packets)
3 cups boiling water
1 tbsp cornstarch
Melt the butter in the oil in a large skillet. Add the onion wedges and roast. Brown the beef on all sides. Transfer the beef and onion to the slow cooker.
Arrange the potatoes, carrots, and bay leaves around the roast. Sprinkle the salt over all.
In a heatproof bowl, combine the onion soup mix with the boiling water. Stir until smooth. Pour over the meat and vegetables in the slow cooker. Cover cooker and cook on high 3 1/2 to 4 hours.
In a medium saucepan, combine the cornstarch and about 1 teaspoon water; stir to form a paste. Add 2 cups of the hot liquid from the slow cooker and bring to a boil, stirring until the gravy is thickened. Serve the roast with the vegetables and gravy.
Note: Replace the onion soup mix with onion-mushroom soup mix, if desired.