Step 3: Prepare the Filling
Place the sweetened condensed milk, chocolate chips, and remaining melted butter into a microwave-safe bowl.
Heat in 30-second intervals, stirring between each interval.
Continue until the mixture becomes smooth, glossy, and fully melted.
This usually takes about 1½ to 2 minutes total, depending on your microwave.
Alternative Stovetop Method
If preferred, combine the ingredients in a heatproof bowl placed over gently simmering water.
Stir continuously until smooth and completely melted.
Remove from heat immediately.
Step 4: Assemble the Bars
Pour the warm filling over the partially cooled crust.
Use a spatula to spread it evenly across the surface.
Gently tap the pan on the counter to remove any air bubbles.
Sprinkle lightly with flaky sea salt if desired.
The salt enhances the chocolate flavor and balances the sweetness.
Step 5: Bake
Return the pan to the oven.
Bake for 15 to 18 minutes.
The edges should appear set while the center remains slightly soft.
Avoid overbaking, as the filling will continue to firm up while cooling.
The finished bars should still look slightly glossy in the center when removed from the oven.
Step 6: Cool and Chill
Allow the bars to cool in the pan for approximately 15 minutes.
Transfer the pan to the refrigerator.
Chill for at least 1 hour.
If you're in a hurry, 30 minutes may be sufficient, but a longer chilling time improves texture and slicing.
Once chilled, the bars develop their signature chewy center and rich texture. This is also the perfect stage to customize them with exciting flavor variations.
