In a large heatproof bowl, pour the 2 cups of boiling water over the package of cherry or raspberry flavored gelatin. Whisk continuously for at least 2 minutes, or until the gelatin powder is completely dissolved and there are no granules remaining. This step is critical for a smooth and even set.

Add the entire can of whole berry cranberry sauce to the dissolved gelatin mixture. Stir gently until the cranberry sauce is fully incorporated and evenly distributed throughout the gelatin. The heat from the gelatin will help slightly thin the cranberry sauce, making it easier to mix.

Next, add the undrained crushed pineapple to the mixture. Stir well to combine. If you’re using the optional granulated sugar, add it now and stir until dissolved. If you're using fresh lemon juice, add that in too for an extra pop of brightness.

Gently fold in the chopped pecans or walnuts and the finely chopped celery (if desired). Ensure they are evenly distributed, so every slice of your molded salad gets a bit of crunch and fresh flavor.

Carefully pour the entire mixture into a 6-cup ring mold, a 9x13 inch baking dish, or individual serving dishes if preferred. Make sure your mold is clean and dry before pouring.

Transfer the mold to the refrigerator. Allow it to chill for at least 4-6 hours, or preferably overnight, until the gelatin is completely firm and set. Do not rush this step, as proper setting is key to a beautiful mold.

Once fully set, carefully unmold the Cranberry Jello Salad onto a serving platter. To do this, briefly dip the bottom of the mold in warm water (not hot) for about 10-15 seconds. Run a thin knife around the edge of the mold to loosen the gelatin, then place your serving plate on top and invert the mold. If it doesn't release immediately, gently shake or tap the mold until it slides out. Garnish as desired, perhaps with a few fresh cranberries or a sprig of mint, and serve cold.