1. Preheat your oven to 350°F (175°C). Line a 9×13-inch baking pan with parchment paper, leaving a little overhang on the sides for easy lifting later.

2. In a medium saucepan, gently melt the unsalted butter and white chocolate chips over low heat, stirring continuously until smooth and glossy to prevent scorching.

3. Remove the saucepan from the heat and carefully transfer the melted mixture into a large mixing bowl.

4. Stir in the granulated sugar, vanilla extract, and salt. Whisk until well combined and the sugar starts to dissolve into the warm mixture.

5. Add the eggs one at a time, making sure to mix well and fully incorporate each egg before adding the next.

6. Gently mix in the all-purpose flour until it’s just combined—do not overmix, or the bars can become tough.

7. Pour the batter into the prepared pan and spread it out evenly into all corners with a spatula.

8. Bake in the preheated oven for 25 minutes until the edges just start to turn golden and the center is mostly set but still slightly soft.

9. Remove from the oven and immediately sprinkle the toffee bits evenly over the top of the partially baked bars.

10. Return to the oven and bake for an additional 5 to 10 minutes, keeping a close eye on them until the edges are golden brown and the center is fully set.

11. Allow the bars to cool completely in the pan to let them set properly before lifting out using the parchment overhang and slicing into squares.