With a meringue top.
From the box of A.D. from Lutz, Florida, by way of Pennsylvania in the 1940s, and originating in Ohio in the 1920s.
Butterscotch Pie
1 cup brown sugar
1 egg yolk
1 Tbsp. flour
Butter the size of a walnut
1 c. milk
Boil together until thick, then pour into crust.
Cover with egg white and brown in oven.