Spray a large baking dish with cooking spray and fill it with 2-12 oz pkgs of fresh cranberries.
Cover tightly with foil and place a lid on top. (This will splatter while in the oven, so make sure to at cover tightly with foil.)
Bake at 350 degrees for 1 hour.
While cranberries are still hot, stir in 1 (12 oz) jar of Smucker's Sweet Orange Marmalade (I recommend Smuckers…others I have tried were too bitter) and 3 tablespoons lemon juice.
Stir well to combine, cover and cool completely. (This can be done the day before and allowed to sit, covered, on the counter overnight.)
Stir before spooning into a serving dish.