Step 1: Preheat the Oven

Preheat your oven to 350°F (175°C). Lightly grease a 9×13-inch baking pan with non-stick cooking spray to prevent sticking.

Step 2: Prepare the Base Layer

1. In a large mixing bowl, combine the dry vanilla cake mix, 1 egg, and melted butter.
2. Stir together until the mixture forms a thick dough.
3. Press this dough evenly into the bottom of the prepared baking pan.

Step 3: Make the Toffee Topping

1. In a separate bowl, whisk together the sweetened condensed milk, remaining egg, and vanilla extract until fully combined.
2. Stir in the toffee bits, making sure they are evenly distributed throughout the mixture.

Step 4: Assemble and Bake

1. Pour the toffee mixture evenly over the cake mix layer in the pan.
2. Use a spatula to spread it out evenly, covering the entire surface.
3. Bake for 20-25 minutes, or until the edges are golden brown and the center is set.

Step 5: Cool and Serve

1. Remove the pan from the oven and let the bars cool completely before cutting.
2. Once cooled, slice into squares and enjoy!