Line an 8x8-inch pan with parchment paper, leaving overhang on two sides.
In a medium saucepan over low heat, melt the butter into the sweetened condensed milk, stirring until the butter is fully melted and the mixture is warm.
Remove from the heat and stir in the white chocolate chips until completely smooth and glossy. Stir in the vanilla extract and salt.
Fold in 3/4 cup of the chopped dried cranberries, reserving the remaining 1/4 cup.
Spread the mixture evenly into the prepared pan. Sprinkle the remaining 1/4 cup cranberries over the top and press them in gently.
Refrigerate at least 2 hours until firm. Lift out with the parchment overhang and cut into 36 squares (6 rows by 6 rows).