Prepare the Strawberry Swirl:

1. Make the Strawberry Puree: If using fresh strawberries, blend them into a smooth puree. If using frozen strawberries, thaw and blend until smooth. For a sweeter swirl, add sugar to the puree and stir until dissolved. You can also add lemon juice for a tangy kick.
2. Set Aside the Puree: Place the strawberry puree in a small bowl and set it aside while you prepare the fudge base.

Prepare the Fudge Base:

3. Melt the White Chocolate: In a medium saucepan, combine the white chocolate chips, sweetened condensed milk, and butter. Stir over low heat until the chocolate is melted and the mixture is smooth.
4. Add the Vanilla Extract: Stir in the vanilla extract for added flavor.
5. Pour the Fudge into the Pan: Line an 8×8-inch square pan with parchment paper or lightly grease it. Pour the melted fudge mixture into the pan and spread it into an even layer with a spatula.

Create the Strawberry Swirl:

6. Swirl the Strawberry Puree: Drop spoonfuls of the strawberry puree over the top of the fudge. Using a skewer or a toothpick, gently swirl the puree into the fudge, creating a marbled effect.

Chill the Fudge:

7. Set the Fudge: Refrigerate the fudge for 3 hours, or until it is firm and fully set. The fudge will hold its shape once chilled.

Serve and Slice:

8. Cut into Squares: Once chilled and set, remove the fudge from the refrigerator. Lift it out of the pan using the parchment paper, and cut it into small squares or rectangles.
9. Serve: Serve the Strawberry Swirl Fudge chilled and enjoy the creamy, fruity goodness!