Prepare the Peach Purée: Drain one can of peaches and pulse them in a food processor until you reach your preferred consistency—whether that’s smooth or a bit chunky. (Tip: For an exceptionally silky texture, pass the purée through a fine-mesh strainer to catch any small bits.)

Mix the Pudding Base: In a large bowl, whisk together the cold whole milk and instant pudding mix until completely smooth. Using a flexible spatula, fold in the peach purée until fully incorporated. Cover the bowl and chill in the refrigerator for 30 minutes. In the meantime, drain the second can of peaches and finely dice them.

Whip the Cream Mixture: In a stand mixer fitted with a whisk attachment, beat the cream cheese and powdered sugar on medium speed for about 2 minutes, or until light and fluffy. Scrape down the sides of the bowl as needed. Pour in the cold heavy cream and continue beating on medium speed for 2 to 3 minutes until stiff peaks form.

Fold It Together: Give the chilled pudding mixture a quick stir with a spatula to loosen it up. Gently fold in the whipped cream cheese mixture, ½ cup of the diced peaches, and the mini marshmallows (if using) until completely combined.

Chill and Serve: Transfer the fluff to a large serving bowl. Alternatively, divide the mixture evenly among eight 4-ounce ramekins or dessert glasses placed on a baking sheet. Cover and refrigerate for at least 30 minutes (or up to 2 hours) to set. Garnish with the remaining diced peaches and a sprinkle of mini marshmallows right before serving.