1.Heat The Oil In A Skillet Over Medium Heat, And Brown The Roast On All Sides. Season With Salt And Pepper, And Transfer To A Slow Cooker. 2.Dissolve The Vegetable Bouillon In The Boiling Water, And Pour Into The Slow Cooker. Mix The Pepperoni, Onion, Black Olives, Garlic, And Tomatoes Into The Slow Cooker. 3.Cover, And Cook 4 Hours On High Or 8 Hours On Low.