Preheat the oven to 425 degrees. Line an 8 x 8 baking dish with foil.
Place the saltines in an even layer in the bottom of the baking dish, slightly overlapping them. Sprinkle the crushed pretzels over top of the crackers.
In a medium saucepan, combine the butter and brown sugar over medium heat. Bring to a boil and cook for 2 minutes.
Remove from heat, and stir in condensed milk.
Carefully pour the mixture over top of the crackers and pretzels.
Place the pan in the oven and bake for 10 minutes. Remove from oven and set aside to cool.
In a medium saucepan combine the white chocolate, butter, salt, and sweetened condensed milk. Heat until the white chocolate has melted. Mix well until smooth.
Add the pudding to the white chocolate mixture. Stir until dissolved. Add in the marshmallow cream and stir until combined with other ingredients.
Pour the fudge over top of the cracker crust. Smooth with a spatula
Quickly sprinkle the pecans over top of the hot fudge. Press them down with the palm of your hand.
Refrigerate the fudge until has hardened. Remove from the refrigerator and cut into 30 squares.