Preheat oven to 350 degrees F (175 degrees C). Grease and flour a 9x9 inch baking pan.
In a medium bowl, combine 1 cup flour, baking powder and salt. In a large bowl, cream 1/4 cup butter and 1/2 cup sugar until light and fluffy. Beat in the egg and vanilla. Gradually beat in the flour mixture and 1/4 cup milk. Spread the batter into the prepared pan.
In a medium saucepan, melt 1/4 cup butter. Stir in the 1/2 cup sugar, 2 tablespoons flour, and cinnamon. Gradually stir in 1/3 cup milk. Cook over medium heat, stirring constantly, until the mixture is thickened. Spread evenly over the cake batter.
Bake for 25 minutes in the preheated oven, or until a toothpick inserted into the center of the cake comes out clean. Cool before serving.
Interesting Facts
Jubilees are an old-fashioned Southern dessert that dates back to the late 19th century.
The cake layer is a combination of flour, baking powder, butter, sugar, egg, and milk.
The custard layer is made from butter, sugar, flour, cinnamon, and milk.
Jubilees are best served warm with a dollop of whipped cream or ice cream.