To incorporate fruits like plum or cranberry in a saison recipe, you have several options. You can add fruit puree, juice, or whole fruits directly to the fermenter once primary fermentation has slowed down. This allows the yeast to ferment the additional sugars and helps retain the fruit's natural flavors and aromas. Alternatively, you can add fruit during the brewing process by introducing them during the last 5-10 minutes of the boil or in the whirlpool stage. The choice of fruit, quantity, and method of addition will depend on the desired flavor intensity and your specific saison recipe. Experiment with different fruit combinations and additions to create a unique, well-balanced, and delicious fruit saison.