Melt butter and marshmallows over medium low heat and stir until smooth, melted and incorporated.
Add in malted milk powder
Add in cereal
Add in 2 cups of malted milk balls
Place in a lightly greased 9 x 13 pan
Sprinkle remaining malted milk balls on top and press lightly into cereal.
Notes
Don't overcook the marshmallow, remove from the heat as soon as they are melted. The longer they cook, the harder they will get. You want soft and chewy!
After you place the mixture into your prepared pan, gently press down on it. Don't make them too compact, you want light and chewy, not dense.
Don't over stir, stir just until cereal is coated. The cereal will begin to break down if over stirred.