Place Cream Cheese on counter and allow to get room temperature.Once the cream cheese is soft place in large bowl and mash with a fork. Prepare jello according to package directions. After jello is made pour hot jello over cream cheese and stir until the cream cheese is dissolved into very small pieces. It is best to add a little of the hot jello at the time. (This makes it easier to blend.)After the cream cheese is completely blended with the jello, drain pineapple and add to mixture. Stir in pecans and marshmallows(optional). Lightly butter a 13 x 9 corning ware dish and slowly pour in jello mixture. Carefully cover with press n seal. Place in fridge until jello is completely set.(About 4 hours).