Instructions:

Preheat and Prepare:

Preheat your oven to 350°F (175°C).
Grease a 9×13-inch baking pan or line it with parchment paper for easy removal.

Make the Base:

In a large mixing bowl, combine the yellow cake mix, melted butter, and egg. Mix until a thick dough forms.
Press two-thirds of the dough evenly into the bottom of the prepared pan, reserving the rest for later.

Add the Filling:

Pour the sweetened condensed milk over the dough layer, spreading it evenly with a spatula.
Sprinkle the semi-sweet chocolate chips and toffee bits over the condensed milk.

Top with Remaining Dough:

Take the reserved dough and crumble it over the top of the chocolate and toffee layer. It’s okay if it doesn’t completely cover the filling; gaps are fine.

Bake:

Bake in the preheated oven for 25-30 minutes, or until the top is lightly golden and the edges are set.

Cool and Serve:

Allow the bars to cool completely in the pan before cutting into squares or rectangles.
Serve and enjoy the gooey, sweet, and crunchy treat!

Tips:

For extra flavor, sprinkle a pinch of sea salt on top before serving.
These bars store well in an airtight container at room temperature for up to 3 days or in the refrigerator for up to a week.

Enjoy your sweet creation! Let me know how it turns out.