Prep the pan: Line an 8x8-inch (20x20 cm) baking pan with parchment, leaving overhang on two sides for easy lifting.
Lightly grease the parchment.
Crush the strawberries: Place freeze-dried strawberries in a zip-top bag and crush with a rolling pin until you have a mix of fine crumbs and small bits. Set aside.
Melt the base: In a medium, heavy-bottomed saucepan, add white chocolate, sweetened condensed milk, and butter. Set over low heat and stir constantly until completely smooth.
Keep the heat gentle to avoid scorching.
Add flavor: Remove from heat. Stir in vanilla and salt. If using, add a tiny drop of gel color and blend for a soft pink hue.
Fold in strawberries: Gently mix in most of the crushed strawberries, reserving a tablespoon or two for topping.
Fold just until evenly dispersed.
Pour and level: Transfer the mixture to the prepared pan. Smooth the top with an offset spatula. Sprinkle reserved strawberry crumbs over the surface and lightly press so they adhere.
Chill to set: Refrigerate uncovered for 2–3 hours, or until firm enough to slice cleanly.
Slice and serve: Lift the fudge out by the parchment overhang.
Use a warm, sharp knife (wipe between cuts) to slice into neat squares. Enjoy slightly chilled or at room temperature.