- 1 cup 2 sticks unsalted butter, melted
- 1 1/2 cups dark brown sugar (packed)
- 2 large eggs
- 1 tablespoon vanilla extract
- 2 cups all-purpose flour
- 1/4 teaspoon kosher salt
- 2/3 cup toffee bits (I used Heath)
- 1 cup semi-sweet chocolate chips
- 1 14 oz. can sweetened condensed milk
- Preheat oven to 350F. Line an 9-by-13-inch pan with aluminum foil or parchment paper and spray with cooking spray; set aside.
- In a large mixing bowl, combine the melted butter, brown sugar, eggs, and vanilla, and whisk to combine. Add the flour, salt, and stir until just combined, taking care not to over-mix. Fold in the toffee bits and chocolate chips. Pour batter into prepared pan, smoothing it lightly with a spatula or offset knife.
- Pour the can of sweetened condensed milk evenly over the top of the batter.
- Bake for 18 to 23 minutes. The edges will be browned and slightly pulling away from sides of pan. The sweetened condensed milk should be bubbling and turning light brown. Allow bars to cool for at least 2 hours before slicing and serving into 16 squares. I like to refrigerate them before cutting to make them easier to cut. Bars can be stored in an airtight container at room temperature or in the refrigerator for up to 1 week, or in the freezer for up to 3 months.