Butter Scotch Pie (Marie Webb)

Caramelizing brown sugar with butter creates complex flavor compounds through the Maillard reaction while the molasses in brown sugar adds depth. Cooking the custard in a double boiler prevents direct heat from scrambling the egg proteins, allowing them to gently coagulate and thicken the filling uniformly. The cornstarch provides additional insurance against curdling by interfering with protein bonding, while the meringue topping creates a moisture barrier that helps prevent a soggy crust.