In a bowl, mix the peanut butter, powdered sugar, and salt together until well combined. Set aside. Line a muffin tin with cupcake liners.
In a separate bowl, add the white chocolate and heat in the microwave at 50% power for 30 second intervals, mixing well between each interval.
Place about a heaping teaspoon on the bottom of each cupcake liner and swirl to coat the bottom and about a centimeter or two up the sides of the liner. Allow to dry.
Take a piece of the peanut butter and roll into a ball in your hands (this is easier done with freshly washed and dried hands) and place each ball in the cupcake liners and gently press down so that it almost reaches the edges of the liners, but doesn't actually touch.
Drop a teaspoon of fluff over the peanut butter, don't let it touch the sides.
Top the fluff with a Ritz cracker (plain works well, I used honey wheat and it's delicious!).
Pour chocolate over the ritz crackers and vigoursly move the muffin tin on your work surface to move the chocolate down the sides of the filling to surround it and even out the tops until it is smooth. Allow to harden at least 4 hours at room temperature, or 1 hour in the refrigerator.