Line an 8x8-inch pan with parchment paper or aluminum foil.
Place white chocolate chips, sweetened condensed milk, and salt in a medium saucepan with a heavy bottom.
Set saucepan over low heat, stirring frequently until the chips are completely melted.
Scatter about 1/3 of the oreo pieces on the bottom of the prepared pan.
Pour about 1/3 of the white chocolate mixture over the oreo pieces. Smooth it out with a spatula, spreading it as evenly as possible.
Sprinkle another third of the oreo pieces on top and pour about half the remaining chocolate mixture over them, smoothing and spreading it.
Repeat with remaining oreo pieces and white chocolate mixture. Refrigerate until set.