Generously grease or line an 8- x 8-inch (20.5 x 20.5 cm) baking pan with parchment paper.
In a large saucepan, melt the butter over medium heat.
Reduce the heat to medium-low and add the marshmallows. Stir continuously until all the marshmallow melts, resembling melty mozzarella cheese.
Add the milk powder (or buttermilk powder) and vanilla extract and stir until incorporated.
Add the crackers, nuts, and dried fruits. Using a flexible spatula or wooden spoon, stir until everything is well coated with the marshmallow-butter mixture.
Transfer the mixture to the prepared pan. Wear a pair of greased food-safe gloves. When the mixture is cool to the touch, pull, stretch, and knead it a little, using your hands.
Evenly press the mixture into the coated pan using your hands (or a greased spatula). You want the mixture to be about ½ to ¾ inch (1.3 to 2 cm) thick and leveled, so don’t over-flatten it.
Cover and let rest on the counter for 30 minutes.
Cut into 12 to 16 even pieces. Dust all over with milk powder. Enjoy one (or two) and then hide or share the rest of these tempting bites.
Store in an airtight container and eat within a few days.
