This recipe comes from a little pressure cooker cookbook by Joanna White. I love the idea of the cider and molasses! This recipe does have to marinate 24 hours. I recommend chuck roast over bottom round or rump roast which can be dry. If your p.c. didn't come with a trivet, improvise with a small steamer rack or other object that will raise the roast off of the bottom of the pot and not restrict steam flow. If a 6 lb roast is too much, you can 1/2 the recipe and adjust the cooking time. A 3 lb roast will cook in 35 - 45 minutes.