Line an 8×8-inch square pan with parchment paper and lightly grease.

In a medium saucepan, combine sugar, butter, milk, and salt. Stir continuously over medium heat until mixture boils.

Let mixture boil for 4–5 minutes until it reaches soft-ball stage.

Remove from heat and stir in marshmallow creme, white chocolate chips, and vanilla until smooth.

Pour into prepared pan and spread evenly.

Add optional swirls or toppings, then allow to cool at room temperature for 2–3 hours.

Cut into squares and store in an airtight container.