Bake the bars at 350°F (175°C) for 18–22 minutes, or until the edges are just starting to bubble and the center looks set but still slightly jiggly. The top should look shiny and glossy, with the pecans lightly toasted.
Cool the pan completely on a wire rack at room temperature. This helps the layers settle so they cut cleanly later and don’t slide apart.
Once cooled, cover the glass casserole dish tightly with plastic wrap or a lid and refrigerate for at least 3 hours, or overnight. This is when the magic happens—the bars firm up into those classic icebox squares Grandma kept tucked away for after-dinner snackers.
When ready to serve, remove the pan from the fridge and let it sit on the counter for about 5–10 minutes to soften just slightly. Use a sharp knife to cut into 16 small squares (or more, if you want bite-sized snackers). Wipe the knife between cuts for the cleanest edges.
