Bake the crust according to the directions on the package. Set aside to cool completely.
Combine the fruit, one cup of the sugar, the orange marmalade, and the orange zest in a medium-size saucepan. Cook over medium heat, stirring occasionally until the mixture thickens a little and a few cranberries pop. This should take approximately eight to nine minutes. Remove from the heat and set aside.
Sprinkle the package of gelatin evenly over 1/3 cup of cold water. Let this mixture sit for one minute and add the contents to the cranberry mixture. Stir to combine.
Let the fruit mixture cool for two hours.
After two hours, pour the fruit mixture into the pie crust and spread out evenly. (The mixture will still be thin.)
Cover the dish with plastic wrap and refrigerate for a minimum of two hours for the filling to thicken up and set.
To make the whipped cream, combine the heavy cream and one tablespoon of sugar in a cold medium-size bowl and use an electric mixer to whip until stiff peaks form. This should take about two to three minutes.
Before serving, top the pie with a generous amount of whipped cream and add any seasonal decorations you like.
This is a dessert for lovers of cranberries, and it is more tart than most fruit pies. If you would like to sweeten things up a bit, you can increase the amount of sugar by an additional one-half cup added to the cranberries.I found the cute sanded gummy Christmas tree candy at Fresh Market, but you can use any candy or other holiday-themed decoration on your pie. Sugared cranberries would also be beautiful. Another DIY idea would be to dip a rosemary sprig into Karo syrup, dredge it in sugar and let dry.You can make this dessert ahead. Make it as directed, cover it, and store it in the refrigerator for three to four days. For the best results, wait to add the whipped cream until you are ready to serve it.I used a purchased frozen pie crust to make this recipe. However, you can certainly make your own crust and use a pie plate or tart pan. I haven't tried it, but I think it would also be delicious with a graham cracker or gingersnap crust.If you use a purchased crust, don't skip the step of liberally pricking the crust's bottom and sides with a fork. You don't want your crust to puff up in spots while baking.Also, I always take the extra step of placing a crumbled piece of parchment paper on the crust bottom. I then fill the parchment-covered pie crust with either dry beans or pie weights. I remove the parchment paper and dry beans when about two or three minutes of baking remains, and then let it finish baking to crisp up the bottom crust.